来个大佬帮我一下

尝试删除服务端根目录下的几个 yml 文件

还是报错无法解决

上传完整的 log

[19:39:20] [Server thread/INFO]: [Coupons] Enabling Coupons v1.0.0
[19:39:20] [Server thread/ERROR]: Could not call method 'public static org.bukkit.inventory.meta.ItemMeta org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaItem$SerializableMeta.deserialize(java.util.Map) throws java.lang.Throwable' of class org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaItem$SerializableMeta for deserialization
java.lang.IllegalArgumentException: ItemFlags([HIDE_ENCHANTS, HIDE_ATTRIBUTES, HIDE_UNBREAKABLE, HIDE_DESTROYS, HIDE_PLACED_ON, HIDE_POTION_EFFECTS]) is not a valid interface java.util.Set
        at org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaItem$SerializableMeta.getObject(CraftMetaItem.java:191) ~[spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaItem.<init>(CraftMetaItem.java:509) ~[spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at sun.reflect.GeneratedConstructorAccessor13.newInstance(Unknown Source) ~[?:?]
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) ~[?:1.8.0_211]
        at java.lang.reflect.Constructor.newInstance(Unknown Source) ~[?:1.8.0_211]
        at org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaItem$SerializableMeta.deserialize(CraftMetaItem.java:156) ~[spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at sun.reflect.GeneratedMethodAccessor6.invoke(Unknown Source) ~[?:?]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_211]
        at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_211]
        at org.bukkit.configuration.serialization.ConfigurationSerialization.deserializeViaMethod(ConfigurationSerialization.java:77) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.serialization.ConfigurationSerialization.deserialize(ConfigurationSerialization.java:117) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.serialization.ConfigurationSerialization.deserializeObject(ConfigurationSerialization.java:195) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConstructor$ConstructCustomObject.construct(YamlConstructor.java:35) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping2ndStep(BaseConstructor.java:373) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor.constructMapping2ndStep(SafeConstructor.java:147) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping(BaseConstructor.java:354) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor$ConstructYamlMap.construct(SafeConstructor.java:489) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConstructor$ConstructCustomObject.construct(YamlConstructor.java:26) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructSequenceStep2(BaseConstructor.java:275) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructSequence(BaseConstructor.java:246) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor$ConstructYamlSeq.construct(SafeConstructor.java:470) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping2ndStep(BaseConstructor.java:373) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor.constructMapping2ndStep(SafeConstructor.java:147) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping(BaseConstructor.java:354) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor$ConstructYamlMap.construct(SafeConstructor.java:489) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConstructor$ConstructCustomObject.construct(YamlConstructor.java:26) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping2ndStep(BaseConstructor.java:373) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor.constructMapping2ndStep(SafeConstructor.java:147) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping(BaseConstructor.java:354) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor$ConstructYamlMap.construct(SafeConstructor.java:489) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConstructor$ConstructCustomObject.construct(YamlConstructor.java:26) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping2ndStep(BaseConstructor.java:373) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor.constructMapping2ndStep(SafeConstructor.java:147) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping(BaseConstructor.java:354) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor$ConstructYamlMap.construct(SafeConstructor.java:489) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConstructor$ConstructCustomObject.construct(YamlConstructor.java:26) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructDocument(BaseConstructor.java:141) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.getSingleData(BaseConstructor.java:127) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.Yaml.loadFromReader(Yaml.java:450) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.Yaml.load(Yaml.java:369) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConfiguration.loadFromString(YamlConfiguration.java:54) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.FileConfiguration.load(FileConfiguration.java:184) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.FileConfiguration.load(FileConfiguration.java:130) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConfiguration.loadConfiguration(YamlConfiguration.java:179) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at com.mchim.Coupons.File.FileManager.load(FileManager.java:18) [Coupons.jar:?]
        at com.mchim.Coupons.LMMain.onEnable(LMMain.java:46) [Coupons.jar:?]
        at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:271) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:337) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:405) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.craftbukkit.v1_11_R1.CraftServer.enablePlugin(CraftServer.java:376) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.craftbukkit.v1_11_R1.CraftServer.enablePlugins(CraftServer.java:326) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at net.minecraft.server.v1_11_R1.MinecraftServer.t(MinecraftServer.java:421) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at net.minecraft.server.v1_11_R1.MinecraftServer.l(MinecraftServer.java:382) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at net.minecraft.server.v1_11_R1.MinecraftServer.a(MinecraftServer.java:337) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at net.minecraft.server.v1_11_R1.DedicatedServer.init(DedicatedServer.java:272) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at net.minecraft.server.v1_11_R1.MinecraftServer.run(MinecraftServer.java:544) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at java.lang.Thread.run(Unknown Source) [?:1.8.0_211]
[19:39:20] [Server thread/ERROR]: Could not call method 'public static org.bukkit.inventory.meta.ItemMeta org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaItem$SerializableMeta.deserialize(java.util.Map) throws java.lang.Throwable' of class org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaItem$SerializableMeta for deserialization
java.lang.IllegalArgumentException: ItemFlags([HIDE_ENCHANTS, HIDE_ATTRIBUTES, HIDE_UNBREAKABLE, HIDE_DESTROYS, HIDE_PLACED_ON, HIDE_POTION_EFFECTS]) is not a valid interface java.util.Set
        at org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaItem$SerializableMeta.getObject(CraftMetaItem.java:191) ~[spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaItem.<init>(CraftMetaItem.java:509) ~[spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaLeatherArmor.<init>(CraftMetaLeatherArmor.java:45) ~[spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[?:1.8.0_211]
        at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source) ~[?:1.8.0_211]
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) ~[?:1.8.0_211]
        at java.lang.reflect.Constructor.newInstance(Unknown Source) ~[?:1.8.0_211]
        at org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaItem$SerializableMeta.deserialize(CraftMetaItem.java:156) ~[spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at sun.reflect.GeneratedMethodAccessor6.invoke(Unknown Source) ~[?:?]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_211]
        at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_211]
        at org.bukkit.configuration.serialization.ConfigurationSerialization.deserializeViaMethod(ConfigurationSerialization.java:77) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.serialization.ConfigurationSerialization.deserialize(ConfigurationSerialization.java:117) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.serialization.ConfigurationSerialization.deserializeObject(ConfigurationSerialization.java:195) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConstructor$ConstructCustomObject.construct(YamlConstructor.java:35) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping2ndStep(BaseConstructor.java:373) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor.constructMapping2ndStep(SafeConstructor.java:147) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping(BaseConstructor.java:354) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor$ConstructYamlMap.construct(SafeConstructor.java:489) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConstructor$ConstructCustomObject.construct(YamlConstructor.java:26) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructSequenceStep2(BaseConstructor.java:275) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructSequence(BaseConstructor.java:246) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor$ConstructYamlSeq.construct(SafeConstructor.java:470) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping2ndStep(BaseConstructor.java:373) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor.constructMapping2ndStep(SafeConstructor.java:147) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping(BaseConstructor.java:354) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor$ConstructYamlMap.construct(SafeConstructor.java:489) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConstructor$ConstructCustomObject.construct(YamlConstructor.java:26) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping2ndStep(BaseConstructor.java:373) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor.constructMapping2ndStep(SafeConstructor.java:147) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping(BaseConstructor.java:354) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor$ConstructYamlMap.construct(SafeConstructor.java:489) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConstructor$ConstructCustomObject.construct(YamlConstructor.java:26) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping2ndStep(BaseConstructor.java:373) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor.constructMapping2ndStep(SafeConstructor.java:147) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping(BaseConstructor.java:354) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor$ConstructYamlMap.construct(SafeConstructor.java:489) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConstructor$ConstructCustomObject.construct(YamlConstructor.java:26) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructDocument(BaseConstructor.java:141) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.getSingleData(BaseConstructor.java:127) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.Yaml.loadFromReader(Yaml.java:450) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.Yaml.load(Yaml.java:369) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConfiguration.loadFromString(YamlConfiguration.java:54) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.FileConfiguration.load(FileConfiguration.java:184) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.FileConfiguration.load(FileConfiguration.java:130) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConfiguration.loadConfiguration(YamlConfiguration.java:179) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at com.mchim.Coupons.File.FileManager.load(FileManager.java:18) [Coupons.jar:?]
        at com.mchim.Coupons.LMMain.onEnable(LMMain.java:46) [Coupons.jar:?]
        at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:271) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:337) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:405) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.craftbukkit.v1_11_R1.CraftServer.enablePlugin(CraftServer.java:376) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.craftbukkit.v1_11_R1.CraftServer.enablePlugins(CraftServer.java:326) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at net.minecraft.server.v1_11_R1.MinecraftServer.t(MinecraftServer.java:421) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at net.minecraft.server.v1_11_R1.MinecraftServer.l(MinecraftServer.java:382) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at net.minecraft.server.v1_11_R1.MinecraftServer.a(MinecraftServer.java:337) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at net.minecraft.server.v1_11_R1.DedicatedServer.init(DedicatedServer.java:272) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at net.minecraft.server.v1_11_R1.MinecraftServer.run(MinecraftServer.java:544) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at java.lang.Thread.run(Unknown Source) [?:1.8.0_211]
[19:39:20] [Server thread/ERROR]: Could not call method 'public static org.bukkit.inventory.meta.ItemMeta org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaItem$SerializableMeta.deserialize(java.util.Map) throws java.lang.Throwable' of class org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaItem$SerializableMeta for deserialization
java.lang.IllegalArgumentException: ItemFlags([HIDE_ENCHANTS, HIDE_ATTRIBUTES, HIDE_UNBREAKABLE, HIDE_DESTROYS, HIDE_PLACED_ON, HIDE_POTION_EFFECTS]) is not a valid interface java.util.Set
        at org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaItem$SerializableMeta.getObject(CraftMetaItem.java:191) ~[spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaItem.<init>(CraftMetaItem.java:509) ~[spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaLeatherArmor.<init>(CraftMetaLeatherArmor.java:45) ~[spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at sun.reflect.GeneratedConstructorAccessor22.newInstance(Unknown Source) ~[?:?]
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) ~[?:1.8.0_211]
        at java.lang.reflect.Constructor.newInstance(Unknown Source) ~[?:1.8.0_211]
        at org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaItem$SerializableMeta.deserialize(CraftMetaItem.java:156) ~[spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at sun.reflect.GeneratedMethodAccessor6.invoke(Unknown Source) ~[?:?]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_211]
        at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_211]
        at org.bukkit.configuration.serialization.ConfigurationSerialization.deserializeViaMethod(ConfigurationSerialization.java:77) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.serialization.ConfigurationSerialization.deserialize(ConfigurationSerialization.java:117) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.serialization.ConfigurationSerialization.deserializeObject(ConfigurationSerialization.java:195) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConstructor$ConstructCustomObject.construct(YamlConstructor.java:35) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping2ndStep(BaseConstructor.java:373) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor.constructMapping2ndStep(SafeConstructor.java:147) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping(BaseConstructor.java:354) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor$ConstructYamlMap.construct(SafeConstructor.java:489) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConstructor$ConstructCustomObject.construct(YamlConstructor.java:26) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructSequenceStep2(BaseConstructor.java:275) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructSequence(BaseConstructor.java:246) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor$ConstructYamlSeq.construct(SafeConstructor.java:470) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping2ndStep(BaseConstructor.java:373) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor.constructMapping2ndStep(SafeConstructor.java:147) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping(BaseConstructor.java:354) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor$ConstructYamlMap.construct(SafeConstructor.java:489) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConstructor$ConstructCustomObject.construct(YamlConstructor.java:26) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping2ndStep(BaseConstructor.java:373) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor.constructMapping2ndStep(SafeConstructor.java:147) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping(BaseConstructor.java:354) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor$ConstructYamlMap.construct(SafeConstructor.java:489) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConstructor$ConstructCustomObject.construct(YamlConstructor.java:26) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping2ndStep(BaseConstructor.java:373) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor.constructMapping2ndStep(SafeConstructor.java:147) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping(BaseConstructor.java:354) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor$ConstructYamlMap.construct(SafeConstructor.java:489) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConstructor$ConstructCustomObject.construct(YamlConstructor.java:26) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructDocument(BaseConstructor.java:141) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.getSingleData(BaseConstructor.java:127) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.Yaml.loadFromReader(Yaml.java:450) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.Yaml.load(Yaml.java:369) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConfiguration.loadFromString(YamlConfiguration.java:54) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.FileConfiguration.load(FileConfiguration.java:184) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.FileConfiguration.load(FileConfiguration.java:130) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConfiguration.loadConfiguration(YamlConfiguration.java:179) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at com.mchim.Coupons.File.FileManager.load(FileManager.java:18) [Coupons.jar:?]
        at com.mchim.Coupons.LMMain.onEnable(LMMain.java:46) [Coupons.jar:?]
        at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:271) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:337) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:405) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.craftbukkit.v1_11_R1.CraftServer.enablePlugin(CraftServer.java:376) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.craftbukkit.v1_11_R1.CraftServer.enablePlugins(CraftServer.java:326) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at net.minecraft.server.v1_11_R1.MinecraftServer.t(MinecraftServer.java:421) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at net.minecraft.server.v1_11_R1.MinecraftServer.l(MinecraftServer.java:382) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at net.minecraft.server.v1_11_R1.MinecraftServer.a(MinecraftServer.java:337) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at net.minecraft.server.v1_11_R1.DedicatedServer.init(DedicatedServer.java:272) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at net.minecraft.server.v1_11_R1.MinecraftServer.run(MinecraftServer.java:544) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at java.lang.Thread.run(Unknown Source) [?:1.8.0_211]
[19:39:20] [Server thread/ERROR]: Could not call method 'public static org.bukkit.inventory.meta.ItemMeta org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaItem$SerializableMeta.deserialize(java.util.Map) throws java.lang.Throwable' of class org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaItem$SerializableMeta for deserialization
java.lang.IllegalArgumentException: ItemFlags([HIDE_ENCHANTS, HIDE_ATTRIBUTES, HIDE_UNBREAKABLE, HIDE_DESTROYS, HIDE_PLACED_ON, HIDE_POTION_EFFECTS]) is not a valid interface java.util.Set
        at org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaItem$SerializableMeta.getObject(CraftMetaItem.java:191) ~[spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaItem.<init>(CraftMetaItem.java:509) ~[spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaLeatherArmor.<init>(CraftMetaLeatherArmor.java:45) ~[spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at sun.reflect.GeneratedConstructorAccessor22.newInstance(Unknown Source) ~[?:?]
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) ~[?:1.8.0_211]
        at java.lang.reflect.Constructor.newInstance(Unknown Source) ~[?:1.8.0_211]
        at org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaItem$SerializableMeta.deserialize(CraftMetaItem.java:156) ~[spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at sun.reflect.GeneratedMethodAccessor6.invoke(Unknown Source) ~[?:?]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_211]
        at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_211]
        at org.bukkit.configuration.serialization.ConfigurationSerialization.deserializeViaMethod(ConfigurationSerialization.java:77) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.serialization.ConfigurationSerialization.deserialize(ConfigurationSerialization.java:117) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.serialization.ConfigurationSerialization.deserializeObject(ConfigurationSerialization.java:195) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConstructor$ConstructCustomObject.construct(YamlConstructor.java:35) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping2ndStep(BaseConstructor.java:373) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor.constructMapping2ndStep(SafeConstructor.java:147) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping(BaseConstructor.java:354) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor$ConstructYamlMap.construct(SafeConstructor.java:489) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConstructor$ConstructCustomObject.construct(YamlConstructor.java:26) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructSequenceStep2(BaseConstructor.java:275) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructSequence(BaseConstructor.java:246) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor$ConstructYamlSeq.construct(SafeConstructor.java:470) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping2ndStep(BaseConstructor.java:373) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor.constructMapping2ndStep(SafeConstructor.java:147) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping(BaseConstructor.java:354) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor$ConstructYamlMap.construct(SafeConstructor.java:489) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConstructor$ConstructCustomObject.construct(YamlConstructor.java:26) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping2ndStep(BaseConstructor.java:373) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor.constructMapping2ndStep(SafeConstructor.java:147) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping(BaseConstructor.java:354) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor$ConstructYamlMap.construct(SafeConstructor.java:489) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConstructor$ConstructCustomObject.construct(YamlConstructor.java:26) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping2ndStep(BaseConstructor.java:373) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor.constructMapping2ndStep(SafeConstructor.java:147) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping(BaseConstructor.java:354) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor$ConstructYamlMap.construct(SafeConstructor.java:489) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConstructor$ConstructCustomObject.construct(YamlConstructor.java:26) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructDocument(BaseConstructor.java:141) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.getSingleData(BaseConstructor.java:127) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.Yaml.loadFromReader(Yaml.java:450) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.Yaml.load(Yaml.java:369) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConfiguration.loadFromString(YamlConfiguration.java:54) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.FileConfiguration.load(FileConfiguration.java:184) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.FileConfiguration.load(FileConfiguration.java:130) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConfiguration.loadConfiguration(YamlConfiguration.java:179) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at com.mchim.Coupons.File.FileManager.load(FileManager.java:18) [Coupons.jar:?]
        at com.mchim.Coupons.LMMain.onEnable(LMMain.java:46) [Coupons.jar:?]
        at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:271) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:337) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:405) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.craftbukkit.v1_11_R1.CraftServer.enablePlugin(CraftServer.java:376) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.craftbukkit.v1_11_R1.CraftServer.enablePlugins(CraftServer.java:326) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at net.minecraft.server.v1_11_R1.MinecraftServer.t(MinecraftServer.java:421) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at net.minecraft.server.v1_11_R1.MinecraftServer.l(MinecraftServer.java:382) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at net.minecraft.server.v1_11_R1.MinecraftServer.a(MinecraftServer.java:337) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at net.minecraft.server.v1_11_R1.DedicatedServer.init(DedicatedServer.java:272) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at net.minecraft.server.v1_11_R1.MinecraftServer.run(MinecraftServer.java:544) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at java.lang.Thread.run(Unknown Source) [?:1.8.0_211]
[19:39:20] [Server thread/ERROR]: Could not call method 'public static org.bukkit.inventory.meta.ItemMeta org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaItem$SerializableMeta.deserialize(java.util.Map) throws java.lang.Throwable' of class org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaItem$SerializableMeta for deserialization
java.lang.IllegalArgumentException: ItemFlags([HIDE_ENCHANTS, HIDE_ATTRIBUTES, HIDE_UNBREAKABLE, HIDE_DESTROYS, HIDE_PLACED_ON, HIDE_POTION_EFFECTS]) is not a valid interface java.util.Set
        at org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaItem$SerializableMeta.getObject(CraftMetaItem.java:191) ~[spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaItem.<init>(CraftMetaItem.java:509) ~[spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaLeatherArmor.<init>(CraftMetaLeatherArmor.java:45) ~[spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at sun.reflect.GeneratedConstructorAccessor22.newInstance(Unknown Source) ~[?:?]
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) ~[?:1.8.0_211]
        at java.lang.reflect.Constructor.newInstance(Unknown Source) ~[?:1.8.0_211]
        at org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaItem$SerializableMeta.deserialize(CraftMetaItem.java:156) ~[spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at sun.reflect.GeneratedMethodAccessor6.invoke(Unknown Source) ~[?:?]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_211]
        at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_211]
        at org.bukkit.configuration.serialization.ConfigurationSerialization.deserializeViaMethod(ConfigurationSerialization.java:77) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.serialization.ConfigurationSerialization.deserialize(ConfigurationSerialization.java:117) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.serialization.ConfigurationSerialization.deserializeObject(ConfigurationSerialization.java:195) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConstructor$ConstructCustomObject.construct(YamlConstructor.java:35) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping2ndStep(BaseConstructor.java:373) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor.constructMapping2ndStep(SafeConstructor.java:147) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping(BaseConstructor.java:354) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor$ConstructYamlMap.construct(SafeConstructor.java:489) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConstructor$ConstructCustomObject.construct(YamlConstructor.java:26) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructSequenceStep2(BaseConstructor.java:275) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructSequence(BaseConstructor.java:246) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor$ConstructYamlSeq.construct(SafeConstructor.java:470) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping2ndStep(BaseConstructor.java:373) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor.constructMapping2ndStep(SafeConstructor.java:147) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping(BaseConstructor.java:354) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor$ConstructYamlMap.construct(SafeConstructor.java:489) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConstructor$ConstructCustomObject.construct(YamlConstructor.java:26) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping2ndStep(BaseConstructor.java:373) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor.constructMapping2ndStep(SafeConstructor.java:147) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping(BaseConstructor.java:354) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor$ConstructYamlMap.construct(SafeConstructor.java:489) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConstructor$ConstructCustomObject.construct(YamlConstructor.java:26) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping2ndStep(BaseConstructor.java:373) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor.constructMapping2ndStep(SafeConstructor.java:147) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping(BaseConstructor.java:354) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor$ConstructYamlMap.construct(SafeConstructor.java:489) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConstructor$ConstructCustomObject.construct(YamlConstructor.java:26) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructDocument(BaseConstructor.java:141) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.getSingleData(BaseConstructor.java:127) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.Yaml.loadFromReader(Yaml.java:450) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.Yaml.load(Yaml.java:369) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConfiguration.loadFromString(YamlConfiguration.java:54) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.FileConfiguration.load(FileConfiguration.java:184) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.FileConfiguration.load(FileConfiguration.java:130) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConfiguration.loadConfiguration(YamlConfiguration.java:179) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at com.mchim.Coupons.File.FileManager.load(FileManager.java:18) [Coupons.jar:?]
        at com.mchim.Coupons.LMMain.onEnable(LMMain.java:46) [Coupons.jar:?]
        at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:271) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:337) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:405) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.craftbukkit.v1_11_R1.CraftServer.enablePlugin(CraftServer.java:376) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.craftbukkit.v1_11_R1.CraftServer.enablePlugins(CraftServer.java:326) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at net.minecraft.server.v1_11_R1.MinecraftServer.t(MinecraftServer.java:421) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at net.minecraft.server.v1_11_R1.MinecraftServer.l(MinecraftServer.java:382) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at net.minecraft.server.v1_11_R1.MinecraftServer.a(MinecraftServer.java:337) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at net.minecraft.server.v1_11_R1.DedicatedServer.init(DedicatedServer.java:272) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at net.minecraft.server.v1_11_R1.MinecraftServer.run(MinecraftServer.java:544) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at java.lang.Thread.run(Unknown Source) [?:1.8.0_211]
[19:39:20] [Server thread/ERROR]: Could not call method 'public static org.bukkit.inventory.meta.ItemMeta org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaItem$SerializableMeta.deserialize(java.util.Map) throws java.lang.Throwable' of class org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaItem$SerializableMeta for deserialization
java.lang.IllegalArgumentException: ItemFlags([HIDE_ENCHANTS, HIDE_ATTRIBUTES, HIDE_UNBREAKABLE, HIDE_DESTROYS, HIDE_PLACED_ON, HIDE_POTION_EFFECTS]) is not a valid interface java.util.Set
        at org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaItem$SerializableMeta.getObject(CraftMetaItem.java:191) ~[spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaItem.<init>(CraftMetaItem.java:509) ~[spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at sun.reflect.GeneratedConstructorAccessor13.newInstance(Unknown Source) ~[?:?]
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) ~[?:1.8.0_211]
        at java.lang.reflect.Constructor.newInstance(Unknown Source) ~[?:1.8.0_211]
        at org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaItem$SerializableMeta.deserialize(CraftMetaItem.java:156) ~[spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at sun.reflect.GeneratedMethodAccessor6.invoke(Unknown Source) ~[?:?]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_211]
        at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_211]
        at org.bukkit.configuration.serialization.ConfigurationSerialization.deserializeViaMethod(ConfigurationSerialization.java:77) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.serialization.ConfigurationSerialization.deserialize(ConfigurationSerialization.java:117) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.serialization.ConfigurationSerialization.deserializeObject(ConfigurationSerialization.java:195) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConstructor$ConstructCustomObject.construct(YamlConstructor.java:35) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping2ndStep(BaseConstructor.java:373) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor.constructMapping2ndStep(SafeConstructor.java:147) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping(BaseConstructor.java:354) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor$ConstructYamlMap.construct(SafeConstructor.java:489) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConstructor$ConstructCustomObject.construct(YamlConstructor.java:26) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructSequenceStep2(BaseConstructor.java:275) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructSequence(BaseConstructor.java:246) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor$ConstructYamlSeq.construct(SafeConstructor.java:470) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping2ndStep(BaseConstructor.java:373) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor.constructMapping2ndStep(SafeConstructor.java:147) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping(BaseConstructor.java:354) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor$ConstructYamlMap.construct(SafeConstructor.java:489) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConstructor$ConstructCustomObject.construct(YamlConstructor.java:26) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping2ndStep(BaseConstructor.java:373) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor.constructMapping2ndStep(SafeConstructor.java:147) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping(BaseConstructor.java:354) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor$ConstructYamlMap.construct(SafeConstructor.java:489) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConstructor$ConstructCustomObject.construct(YamlConstructor.java:26) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping2ndStep(BaseConstructor.java:373) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor.constructMapping2ndStep(SafeConstructor.java:147) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping(BaseConstructor.java:354) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor$ConstructYamlMap.construct(SafeConstructor.java:489) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConstructor$ConstructCustomObject.construct(YamlConstructor.java:26) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructDocument(BaseConstructor.java:141) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.getSingleData(BaseConstructor.java:127) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.Yaml.loadFromReader(Yaml.java:450) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.Yaml.load(Yaml.java:369) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConfiguration.loadFromString(YamlConfiguration.java:54) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.FileConfiguration.load(FileConfiguration.java:184) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.FileConfiguration.load(FileConfiguration.java:130) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConfiguration.loadConfiguration(YamlConfiguration.java:179) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at com.mchim.Coupons.File.FileManager.load(FileManager.java:18) [Coupons.jar:?]
        at com.mchim.Coupons.LMMain.onEnable(LMMain.java:46) [Coupons.jar:?]
        at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:271) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:337) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:405) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.craftbukkit.v1_11_R1.CraftServer.enablePlugin(CraftServer.java:376) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.craftbukkit.v1_11_R1.CraftServer.enablePlugins(CraftServer.java:326) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at net.minecraft.server.v1_11_R1.MinecraftServer.t(MinecraftServer.java:421) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at net.minecraft.server.v1_11_R1.MinecraftServer.l(MinecraftServer.java:382) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at net.minecraft.server.v1_11_R1.MinecraftServer.a(MinecraftServer.java:337) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at net.minecraft.server.v1_11_R1.DedicatedServer.init(DedicatedServer.java:272) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at net.minecraft.server.v1_11_R1.MinecraftServer.run(MinecraftServer.java:544) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at java.lang.Thread.run(Unknown Source) [?:1.8.0_211]
[19:39:20] [Server thread/ERROR]: Could not call method 'public static org.bukkit.inventory.meta.ItemMeta org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaItem$SerializableMeta.deserialize(java.util.Map) throws java.lang.Throwable' of class org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaItem$SerializableMeta for deserialization
java.lang.IllegalArgumentException: ItemFlags([HIDE_ENCHANTS, HIDE_ATTRIBUTES, HIDE_UNBREAKABLE, HIDE_DESTROYS, HIDE_PLACED_ON, HIDE_POTION_EFFECTS]) is not a valid interface java.util.Set
        at org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaItem$SerializableMeta.getObject(CraftMetaItem.java:191) ~[spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaItem.<init>(CraftMetaItem.java:509) ~[spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaLeatherArmor.<init>(CraftMetaLeatherArmor.java:45) ~[spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at sun.reflect.GeneratedConstructorAccessor22.newInstance(Unknown Source) ~[?:?]
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) ~[?:1.8.0_211]
        at java.lang.reflect.Constructor.newInstance(Unknown Source) ~[?:1.8.0_211]
        at org.bukkit.craftbukkit.v1_11_R1.inventory.CraftMetaItem$SerializableMeta.deserialize(CraftMetaItem.java:156) ~[spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at sun.reflect.GeneratedMethodAccessor6.invoke(Unknown Source) ~[?:?]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_211]
        at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_211]
        at org.bukkit.configuration.serialization.ConfigurationSerialization.deserializeViaMethod(ConfigurationSerialization.java:77) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.serialization.ConfigurationSerialization.deserialize(ConfigurationSerialization.java:117) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.serialization.ConfigurationSerialization.deserializeObject(ConfigurationSerialization.java:195) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConstructor$ConstructCustomObject.construct(YamlConstructor.java:35) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping2ndStep(BaseConstructor.java:373) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor.constructMapping2ndStep(SafeConstructor.java:147) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping(BaseConstructor.java:354) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor$ConstructYamlMap.construct(SafeConstructor.java:489) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConstructor$ConstructCustomObject.construct(YamlConstructor.java:26) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructSequenceStep2(BaseConstructor.java:275) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructSequence(BaseConstructor.java:246) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor$ConstructYamlSeq.construct(SafeConstructor.java:470) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping2ndStep(BaseConstructor.java:373) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor.constructMapping2ndStep(SafeConstructor.java:147) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping(BaseConstructor.java:354) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor$ConstructYamlMap.construct(SafeConstructor.java:489) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConstructor$ConstructCustomObject.construct(YamlConstructor.java:26) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping2ndStep(BaseConstructor.java:373) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor.constructMapping2ndStep(SafeConstructor.java:147) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping(BaseConstructor.java:354) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor$ConstructYamlMap.construct(SafeConstructor.java:489) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConstructor$ConstructCustomObject.construct(YamlConstructor.java:26) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping2ndStep(BaseConstructor.java:373) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor.constructMapping2ndStep(SafeConstructor.java:147) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping(BaseConstructor.java:354) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.SafeConstructor$ConstructYamlMap.construct(SafeConstructor.java:489) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConstructor$ConstructCustomObject.construct(YamlConstructor.java:26) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:182) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.constructDocument(BaseConstructor.java:141) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.constructor.BaseConstructor.getSingleData(BaseConstructor.java:127) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.Yaml.loadFromReader(Yaml.java:450) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.yaml.snakeyaml.Yaml.load(Yaml.java:369) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConfiguration.loadFromString(YamlConfiguration.java:54) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.FileConfiguration.load(FileConfiguration.java:184) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.FileConfiguration.load(FileConfiguration.java:130) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.configuration.file.YamlConfiguration.loadConfiguration(YamlConfiguration.java:179) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at com.mchim.Coupons.File.FileManager.load(FileManager.java:18) [Coupons.jar:?]
        at com.mchim.Coupons.LMMain.onEnable(LMMain.java:46) [Coupons.jar:?]
        at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:271) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:337) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:405) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.craftbukkit.v1_11_R1.CraftServer.enablePlugin(CraftServer.java:376) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at org.bukkit.craftbukkit.v1_11_R1.CraftServer.enablePlugins(CraftServer.java:326) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at net.minecraft.server.v1_11_R1.MinecraftServer.t(MinecraftServer.java:421) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at net.minecraft.server.v1_11_R1.MinecraftServer.l(MinecraftServer.java:382) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at net.minecraft.server.v1_11_R1.MinecraftServer.a(MinecraftServer.java:337) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-3fb9445-2b6c9f4]
        at net.minecraft.server.v1_11_R1.DedicatedServer.init(DedicatedServer.java:272) [spigot

本帖最后由 gyq2001 于 2020-6-3 22:47 编辑

使用排除法，先把所有插件剪切到别的文件夹里，加一个插件开一次服，看一次报错，你就能找到是哪几个插件冲突了。有些插件本身写的就不好，很容易刷屏报错。
望采纳

看样子是服务端问题，换个服务端吧
如果不能解决
存档是否重要
不重要就删除存档，顺便可以尝试一下将服务端根目录配置文件用notepad++转码

Coupons.jar
这个插件 (如果这是个插件的话)
在序列化物品的时候出错了 无法自行解决 请联系作者
简单说就是看看这个插件有没有新版本 有的话升级试试
如果没有新版本尝试降级看看

不影响使用的话可以使用屏蔽插件屏蔽报错

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不过长时间刷报错的话可能会占内存吧？（一个老服主告诉我的）

屏蔽之后就不会再出现在控制台里了
如果担心占用内存可以添加自动清理内存的参数

有帮助请您在本回复右下角点击设置最佳答案。
您的认可是对回答者最大的支持！