Error with IntelliJ Ultimate 133.696

[keyboardsurfer]

The plugin won't run with the above version of IntelliJ

Plugin 'Pom sorter' failed to initialize and will be disabled. Please restart IntelliJ IDEA.

com.intellij.diagnostic.PluginException: pl/itcrowd/pom_sorter/PomSorter : Unsupported major.minor version 51.0 [Plugin: Pom sorter]
at com.intellij.ide.plugins.cl.PluginClassLoader.b(PluginClassLoader.java:130)
at com.intellij.ide.plugins.cl.PluginClassLoader.a(PluginClassLoader.java:77)
at com.intellij.ide.plugins.cl.PluginClassLoader.loadClass(PluginClassLoader.java:66)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:249)
at com.intellij.openapi.components.impl.ComponentManagerImpl$ComponentsRegistry.a(ComponentManagerImpl.java:408)
at com.intellij.openapi.components.impl.ComponentManagerImpl$ComponentsRegistry.a(ComponentManagerImpl.java:398)
at com.intellij.openapi.components.impl.ComponentManagerImpl$ComponentsRegistry.access$000(ComponentManagerImpl.java:384)
at com.intellij.openapi.components.impl.ComponentManagerImpl.a(ComponentManagerImpl.java:107)
at com.intellij.openapi.components.impl.ComponentManagerImpl.init(ComponentManagerImpl.java:89)
at com.intellij.openapi.project.impl.ProjectImpl.init(ProjectImpl.java:307)
at com.intellij.openapi.project.impl.ProjectManagerImpl.a(ProjectManagerImpl.java:278)
at com.intellij.openapi.project.impl.ProjectManagerImpl.access$300(ProjectManagerImpl.java:82)
at com.intellij.openapi.project.impl.ProjectManagerImpl$9.compute(ProjectManagerImpl.java:562)
at com.intellij.openapi.project.impl.ProjectManagerImpl$9.compute(ProjectManagerImpl.java:558)
at com.intellij.openapi.progress.impl.ProgressManagerImpl$4.run(ProgressManagerImpl.java:240)
at com.intellij.openapi.progress.impl.ProgressManagerImpl$TaskRunnable.run(ProgressManagerImpl.java:464)
at com.intellij.openapi.progress.impl.ProgressManagerImpl$6.run(ProgressManagerImpl.java:274)
at com.intellij.openapi.progress.impl.ProgressManagerImpl$2.run(ProgressManagerImpl.java:178)
at com.intellij.openapi.progress.ProgressManager.executeProcessUnderProgress(ProgressManager.java:209)
at com.intellij.openapi.progress.impl.ProgressManagerImpl.executeProcessUnderProgress(ProgressManagerImpl.java:212)
at com.intellij.openapi.progress.impl.ProgressManagerImpl.runProcess(ProgressManagerImpl.java:171)
at com.intellij.openapi.application.impl.ApplicationImpl$10$1.run(ApplicationImpl.java:642)
at com.intellij.openapi.application.impl.ApplicationImpl$8.run(ApplicationImpl.java:420)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:439)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:895)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:918)
at java.lang.Thread.run(Thread.java:695)
at com.intellij.openapi.application.impl.ApplicationImpl$1$1.run(ApplicationImpl.java:150)
Caused by: java.lang.UnsupportedClassVersionError: pl/itcrowd/pom_sorter/PomSorter : Unsupported major.minor version 51.0
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClassCond(ClassLoader.java:637)
at java.lang.ClassLoader.defineClass(ClassLoader.java:621)
at java.lang.ClassLoader.defineClass(ClassLoader.java:471)
at com.intellij.util.lang.UrlClassLoader._defineClass(UrlClassLoader.java:189)
at com.intellij.util.lang.UrlClassLoader.defineClass(UrlClassLoader.java:185)
at com.intellij.util.lang.UrlClassLoader._findClass(UrlClassLoader.java:161)
at com.intellij.ide.plugins.cl.PluginClassLoader.b(PluginClassLoader.java:124)
... 31 more

[blabno]

What version of java do you use (5,6 or 7)?

[keyboardsurfer]

My machine has Java 7 installed.

[blabno]

Are you sure? Version 51.0 = Java 7.

[keyboardsurfer]

$> java -version
java version "1.7.0_51"
Java(TM) SE Runtime Environment (build 1.7.0_51-b13)
Java HotSpot(TM) 64-Bit Server VM (build 24.51-b03, mixed mode)

[blabno]

Which version of PomSorter do you use?

[keyboardsurfer]

I'm not quite sure, as I have uninstalled it again. Probably 1.0.9 or 1.0.10...