Exception in thread "main" java.lang.UnsupportedClassVersionError: com/mojang/patchy/LegacyXMLLayout : Unsupported major.minor version 52.0
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClass(Unknown Source)
        at java.security.SecureClassLoader.defineClass(Unknown Source)
        at java.net.URLClassLoader.defineClass(Unknown Source)
        at java.net.URLClassLoader.access$100(Unknown Source)
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at org.apache.logging.log4j.core.config.plugins.util.PluginRegistry.decodeCacheFiles(PluginRegistry.java:181)
        at org.apache.logging.log4j.core.config.plugins.util.PluginRegistry.loadFromMainClassLoader(PluginRegistry.java:119)
        at org.apache.logging.log4j.core.config.plugins.util.PluginManager.collectPlugins(PluginManager.java:132)
        at org.apache.logging.log4j.core.pattern.PatternParser.<init>(PatternParser.java:132)
        at org.apache.logging.log4j.core.pattern.PatternParser.<init>(PatternParser.java:113)
        at org.apache.logging.log4j.core.layout.PatternLayout.createPatternParser(PatternLayout.java:246)
        at org.apache.logging.log4j.core.layout.PatternLayout$SerializerBuilder.build(PatternLayout.java:375)
        at org.apache.logging.log4j.core.layout.PatternLayout.<init>(PatternLayout.java:128)
        at org.apache.logging.log4j.core.layout.PatternLayout.<init>(PatternLayout.java:58)
        at org.apache.logging.log4j.core.layout.PatternLayout$Builder.build(PatternLayout.java:652)
        at org.apache.logging.log4j.core.config.AbstractConfiguration.setToDefault(AbstractConfiguration.java:577)
        at org.apache.logging.log4j.core.config.DefaultConfiguration.<init>(DefaultConfiguration.java:47)
        at org.apache.logging.log4j.core.LoggerContext.<init>(LoggerContext.java:86)
        at org.apache.logging.log4j.core.selector.ClassLoaderContextSelector.createContext(ClassLoaderContextSelector.java:171)
        at org.apache.logging.log4j.core.selector.ClassLoaderContextSelector.locateContext(ClassLoaderContextSelector.java:145)
        at org.apache.logging.log4j.core.selector.ClassLoaderContextSelector.getContext(ClassLoaderContextSelector.java:74)
        at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:227)
        at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:45)
        at org.apache.logging.log4j.LogManager.getContext(LogManager.java:174)
        at org.apache.logging.log4j.LogManager.getLogger(LogManager.java:618)
        at net.minecraft.launchwrapper.LogWrapper.configureLogging(LogWrapper.java:14)
        at net.minecraft.launchwrapper.LogWrapper.log(LogWrapper.java:28)
        at net.minecraft.launchwrapper.Launch.launch(Launch.java:94)
        at net.minecraft.launchwrapper.Launch.main(Launch.java:2

把你的java换成最新版
直接到www.java.com可以下载

换成最新版本就可以啦？

还是蹦 你看

Error occurred during initialization of VM
[PCL] Minecraft 已退出，返回值：1
[PCL] Minecraft 窗口未出现
[PCL] 如果你需要其它人的帮助，请将本窗口内的所有内容都发送给对方

Plain Craft Launcher 诊断信息
——————————————————
启动器版本：1.0.3（43）
Java 路径：C:\Program Files (x86)\Common Files\Oracle\Java\javapath
Java 版本：8.0.2210.11
关闭 MC 后的内存剩余：5576M / 8087M
分配的内存：3500M
Minecraft 文件夹：F:\新建文件夹 (3)\无限作死1.12.2客服端\.minecraft\
Minecraft 版本文件夹名：1.12.2-forge1.12.2-14.23.0.2494（1.12.2）

本帖最后由 ItIsEnderman 于 2019-7-22 14:29 编辑

那难怪
有可能因为你的浏览器是32位的，导致java.com误认为你的系统是32位的。
你访问这个试试：https://www.java.com/zh_CN/download/windows-64bit.jsp

内存问题

Java 路径：C:\Program Files (x86)\Common Files\Oracle\Java\javapath
你这装的是32位的Java吧。。你得去装个64位的才能分配1g以上内存
启动器也要记得改Java路径

https://www.java.com/en/download/manual.jsp ，下载这个界面的java

重新下载一个Java，要把原来路径的Java删掉好吧

32位的Java不支持1024以上的运存，需要64位的（试一试）

java换64位 内存设置1024以上