Hi Team,

I have upgraded Jenkins to 1.6 and my slave machine went offline. Looking at logs.

As slave.jar is meant to be launched by Jenkins typically through a remote shell like ssh/rsh. It does that step. our Linux server have dump of java not installed traditionally on the server but we use different JDK version on purpose by creating link to dump.

On launching slave machine it tries to find the java on linux machine if not found installs automatically using script jdk.sh. The version it installs is jdk1.6 and also i do not have an option to set JDK later than 1.6 in Tools section of configuration.

After installation i get below error not sure related to jdk or something else. I cannot install later version of JDK as it overrides everything again.

Could you please let me know what is causing this issue??

Is it possible that its because of this http://jenkins-ci.org/content/good-bye-java6

[06/29/15 15:48:37] [SSH] Checking java version of /home/build/Jenkins/jdk/bin/java
[06/29/15 15:48:37] [SSH] /home/build/Jenkins/jdk/bin/java -version returned 1.6.0_45.
[06/29/15 15:48:37] [SSH] Starting sftp client.
[06/29/15 15:48:37] [SSH] Copying latest slave.jar...
[06/29/15 15:48:39] [SSH] Copied 478,472 bytes.
Expanded the channel window size to 4MB
[06/29/15 15:48:39] [SSH] Starting slave process: cd "/home/build/Jenkins" && /home/build/Jenkins/jdk/bin/java -jar slave.jar
<===[JENKINS REMOTING CAPACITY]===>channel started
hudson.util.IOException2: Slave JVM has not reported exit code. Is it still running?
at hudson.plugins.sshslaves.SSHLauncher.startSlave(SSHLauncher.java:953)
at hudson.plugins.sshslaves.SSHLauncher.access$400(SSHLauncher.java:133)
at hudson.plugins.sshslaves.SSHLauncher$2.call(SSHLauncher.java:711)
at hudson.plugins.sshslaves.SSHLauncher$2.call(SSHLauncher.java:696)
at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: java.io.IOException: Remote call on Linux - appsrv2 failed
at hudson.remoting.Channel.call(Channel.java:761)
at hudson.slaves.SlaveComputer.setChannel(SlaveComputer.java:498)
at hudson.slaves.SlaveComputer.setChannel(SlaveComputer.java:371)
at hudson.plugins.sshslaves.SSHLauncher.startSlave(SSHLauncher.java:945)
... 8 more
Caused by: java.lang.ClassFormatError: Failed to load hudson.slaves.SlaveComputer$SlaveVersion
at hudson.remoting.RemoteClassLoader.loadClassFile(RemoteClassLoader.java:325)
at hudson.remoting.RemoteClassLoader.findClass(RemoteClassLoader.java:237)
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 hudson.remoting.MultiClassLoaderSerializer$Input.resolveClass(MultiClassLoaderSerializer.java:113)
at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1589)
at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1494)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1748)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1327)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:349)
at hudson.remoting.UserRequest.deserialize(UserRequest.java:185)
at hudson.remoting.UserRequest.perform(UserRequest.java:99)
at hudson.remoting.UserRequest.perform(UserRequest.java:49)
at hudson.remoting.Request$2.run(Request.java:325)
at hudson.remoting.InterceptingExecutorService$1.call(InterceptingExecutorService.java:68)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
at java.util.con