关于Java 7执行的Java 6文件（或32位文件...）

我tryed运行.jar文件上历时爪哇7.我接收此错误：关于Java 7执行的Java 6文件（或32位文件...）

Could not load 'plugins/ucars.jar' in folder 'plugins' 
org.bukkit.plugin.InvalidPluginException: java.lang.UnsupportedClassVersionError: com/useful/ucars/ucars : Unsupported major.minor version 51.0 
at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:184) 
at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:305) 
at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:230) 
at org.bukkit.craftbukkit.v1_4_R1.CraftServer.loadPlugins(CraftServer.java:239) 
at org.bukkit.craftbukkit.v1_4_R1.CraftServer.<init>(CraftServer.java:217) 
at net.minecraft.server.v1_4_R1.PlayerList.<init>(PlayerList.java:55) 
at net.minecraft.server.v1_4_R1.DedicatedPlayerList.<init>(SourceFile:11) 
at net.minecraft.server.v1_4_R1.DedicatedServer.init(DedicatedServer.java:104) 
at net.minecraft.server.v1_4_R1.MinecraftServer.run(MinecraftServer.java:399) 
at net.minecraft.server.v1_4_R1.ThreadServerApplication.run(SourceFile:849) 
    Caused by: java.lang.UnsupportedClassVersionError: com/useful/ucars/ucars : Unsupported major.minor version 51.0 
at java.lang.ClassLoader.defineClass1(Native Method) 
at java.lang.ClassLoader.defineClassCond(ClassLoader.java:631) 
at java.lang.ClassLoader.defineClass(ClassLoader.java:615) 
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141) 
at java.net.URLClassLoader.defineClass(URLClassLoader.java:283) 
at java.net.URLClassLoader.access$000(URLClassLoader.java:58) 
at java.net.URLClassLoader$1.run(URLClassLoader.java:197) 
at java.security.AccessController.doPrivileged(Native Method) 
at java.net.URLClassLoader.findClass(URLClassLoader.java:190) 
at org.bukkit.plugin.java.PluginClassLoader.findClass0(PluginClassLoader.java:80) 
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:53) 
at java.lang.ClassLoader.loadClass(ClassLoader.java:306) 
at java.lang.ClassLoader.loadClass(ClassLoader.java:247) 
at java.lang.Class.forName0(Native Method) 
at java.lang.Class.forName(Class.java:249) 
at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:173) 
... 9 more

（这是CraftBukkit v1.4.7 R1.0服务器）只有这个插件，.jar，无法正常工作。

如果这是因为Java版本不一样，我该如何在Java 7上运行Java 6文件（？）？

（Mac OS X Lion 10.7.5）

来源

2013-04-05 theShay