我用的是Jenkins。1.565.11.1（jenkins enterprise by cloudbees 14.05）和have jdk 1.5、1.5.0.22、1.6、1.7都已安装，并针对不同的项目使用不同的版本。
我的问题是我错误地用jdk1.7编译了一个项目，但是我不得不用jdk1.5编译它，但是我做不到。获取以下错误：

Exception in thread "main" java.lang.UnsupportedClassVersionError: Bad version number     in .class file
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:621)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:124)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:260)
at java.net.URLClassLoader.access$100(URLClassLoader.java:56)
at java.net.URLClassLoader$1.run(URLClassLoader.java:195)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClassFromSelf(ClassRealm.java:389)
at org.codehaus.plexus.classworlds.strategy.SelfFirstStrategy.loadClass(SelfFirstStrategy.java:42)
at org.codehaus.plexus.classworlds.realm.ClassRealm.unsynchronizedLoadClass(ClassRealm.java:259)
at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:242)
at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:227)
at jenkins.maven3.agent.Maven31Main.main(Maven31Main.java:138)
at jenkins.maven3.agent.Maven31Main.main(Maven31Main.java:67)
ERROR: Failed to parse POMs
java.io.EOFException: unexpected stream termination
at hudson.remoting.ChannelBuilder.negotiate(ChannelBuilder.java:331)
at hudson.remoting.ChannelBuilder.build(ChannelBuilder.java:280)
at hudson.slaves.Channels.forProcess(Channels.java:114)
at hudson.maven.AbstractMavenProcessFactory.newProcess(AbstractMavenProcessFactory.java:280)
at hudson.maven.ProcessCache.get(ProcessCache.java:236)
at hudson.maven.MavenModuleSetBuild$MavenModuleSetBuildExecution.doRun(MavenModuleSetBuild.java:755)
at hudson.model.AbstractBuild$AbstractBuildExecution.run(AbstractBuild.java:529)
at hudson.model.Run.execute(Run.java:1706)
at hudson.maven.MavenModuleSetBuild.run(MavenModuleSetBuild.java:529)
at hudson.model.ResourceController.execute(ResourceController.java:88)
at hudson.model.Executor.run(Executor.java:232)
Finished: FAILURE