Hi

i am using the jenkins in 2.23 version , working fine, but when i upgraded to latest jenkins 2.121 version i am facing issue with java7 projects.

scenario happened

actually, there was a suggestion to upgrade the plugin upgrades from the manage jenkins, so its asked me to restart, when i restarted the jenkins, plugins got updated but most of the jenkins data is not compatible with older jenkins, so we  upgraded to latest version of jenkins 2.121 , when we upgraded, master jenkins running on java8  and even it expecting slave machine to run on java8 forcefully,

when i configuring the jenkins profile with java7 its throwing the same error.

first error

Second error

we  upgraded to latest version of jenkins 2.121 , when we upgraded, master jenkins running on java8  and even it expecting slave machine to run on java8 forcefully,

Jenkins 2.60 and newer requires Java 8 to run Jenkins itself, and 2.75 and newer requires Java 8 for agent machines as well. Are your agent machines running Java 8?

yes, slave machine are forcefully running on java8,  i tried to launch slave machines with java7 but master expecting to run slave machine  on java 8 only.

slave machines are not supporting to java7

while running java7 Projects, it failing to execute the java7 commands

looks like the problems seems to be also with agent.jar and slave.jar 

when mvn tries to run with these jars it fails.
Established TCP socket on 33600
Copied maven32-agent.jar
Copied maven32-interceptor.jar
Copied maven3-interceptor-commons.jar
[jdk7 job] $ /data/jenkins_node/tools/hudson.model.JDK/jdk7/bin/java -cp /data/jenkins_node/maven32-agent.jar:/data/jenkins_node/tools/hudson.tasks.Maven_MavenInstallation/Maven_3.2.2/boot/plexus-classworlds-2.5.1.jar:/data/jenkins_node/tools/hudson.tasks.Maven_MavenInstallation/Maven_3.2.2/conf/logging jenkins.maven3.agent.Maven32Main /data/jenkins_node/tools/hudson.tasks.Maven_MavenInstallation/Maven_3.2.2 /data/jenkins_node/slave.jar /data/jenkins_node/maven32-interceptor.jar /data/jenkins_node/maven3-interceptor-commons.jar 33600
Exception in thread "main" java.lang.UnsupportedClassVersionError: hudson/remoting/Launcher : Unsupported major.minor version 52.0
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:800)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:449)
at java.net.URLClassLoader.access$100(URLClassLoader.java:71)
at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClassFromSelf(ClassRealm.java:389)
at org.codehaus.plexus.classworlds.strategy.SelfFirstStrategy.loadClass(SelfFirstStrategy.java:42)
at org.codehaus.plexus.classworlds.realm.ClassRealm.unsynchronizedLoadClass(ClassRealm.java:259)
at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:235)
at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:227)
at jenkins.maven3.agent.Maven32Main.main(Maven32Main.java:143)
at jenkins.maven3.agent.Maven32Main.main(Maven32Main.java:74)
ERROR: Failed to parse POMs
java.io.EOFException: unexpected stream termination
at hudson.remoting.ChannelBuilder.negotiate(ChannelBuilder.java:411)
at hudson.remoting.ChannelBuilder.build(ChannelBuilder.java:356)
at hudson.slaves.Channels.forProcess(Channels.java:115)
at hudson.maven.AbstractMavenProcessFactory.newProcess(AbstractMavenProcessFactory.java:294)
at hudson.maven.ProcessCache.get(ProcessCache.java:236)
at hudson.maven.MavenModuleSetBuild$MavenModuleSetBuildExecution.doRun(MavenModuleSetBuild.java:804)
at hudson.model.AbstractBuild$AbstractBuildExecution.run(AbstractBuild.java:504)
at hudson.model.Run.execute(Run.java:1815)
at hudson.maven.MavenModuleSetBuild.run(MavenModuleSetBuild.java:543)
at hudson.model.ResourceController.execute(ResourceController.java:97)
at hudson.model.Executor.run(Executor.java:429)
Finished: FAILURE

[root@jenkins1 jenkins_node]# ./exec.sh agent.jar

Exception in thread "main" java.lang.UnsupportedClassVersionError: hudson/remoting/Launcher : Unsupported major.minor version 52.0

at java.lang.ClassLoader.defineClass1(Native Method)

at java.lang.ClassLoader.defineClass(ClassLoader.java:800)

at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)

at java.net.URLClassLoader.defineClass(URLClassLoader.java:449)

at java.net.URLClassLoader.access$100(URLClassLoader.java:71)

at java.net.URLClassLoader$1.run(URLClassLoader.java:361)

at java.net.URLClassLoader$1.run(URLClassLoader.java:355)

at java.security.AccessController.doPrivileged(Native Method)

at java.net.URLClassLoader.findClass(URLClassLoader.java:354)

at java.lang.ClassLoader.loadClass(ClassLoader.java:425)

at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)

at java.lang.ClassLoader.loadClass(ClassLoader.java:358)

at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:482)

[root@jenkins1 jenkins_node]# ./exec.sh slave.jar

Exception in thread "main" java.lang.UnsupportedClassVersionError: hudson/remoting/Launcher : Unsupported major.minor version 52.0

at java.lang.ClassLoader.defineClass1(Native Method)

at java.lang.ClassLoader.defineClass(ClassLoader.java:800)

at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)

at java.net.URLClassLoader.defineClass(URLClassLoader.java:449)

at java.net.URLClassLoader.access$100(URLClassLoader.java:71)

at java.net.URLClassLoader$1.run(URLClassLoader.java:361)

at java.net.URLClassLoader$1.run(URLClassLoader.java:355)

at java.security.AccessController.doPrivileged(Native Method)

at java.net.URLClassLoader.findClass(URLClassLoader.java:354)

at java.lang.ClassLoader.loadClass(ClassLoader.java:425)

at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)

at java.lang.ClassLoader.loadClass(ClassLoader.java:358)

at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:482)

Jenkins no longer supports JDK 8. This won't be fixed.