Docker slaves don't work anymore in Jenkins

[landauf]

[05/26/17 15:27:06] [SSH] Checking java version of java
[05/26/17 15:27:06] [SSH] java -version returned 1.7.0_131.
[05/26/17 15:27:06] [SSH] Starting sftp client.
[05/26/17 15:27:06] [SSH] Copying latest slave.jar...
[05/26/17 15:27:06] [SSH] Copied 719,269 bytes.
Expanded the channel window size to 4MB
[05/26/17 15:27:06] [SSH] Starting slave process: cd "/home/jenkins" && java  -jar slave.jar
<===[JENKINS REMOTING CAPACITY]===>channel started
Slave JVM has not reported exit code. Is it still running?
[05/26/17 15:27:10] Launch failed - cleaning up connection
[05/26/17 15:27:10] [SSH] Connection closed.
ERROR: Connection terminated
java.io.EOFException
	at java.io.ObjectInputStream$PeekInputStream.readFully(ObjectInputStream.java:2638)
	at java.io.ObjectInputStream$BlockDataInputStream.readShort(ObjectInputStream.java:3113)
	at java.io.ObjectInputStream.readStreamHeader(ObjectInputStream.java:853)
	at java.io.ObjectInputStream.<init>(ObjectInputStream.java:349)
	at hudson.remoting.ObjectInputStreamEx.<init>(ObjectInputStreamEx.java:48)
	at hudson.remoting.AbstractSynchronousByteArrayCommandTransport.read(AbstractSynchronousByteArrayCommandTransport.java:34)
	at hudson.remoting.SynchronousCommandTransport$ReaderThread.run(SynchronousCommandTransport.java:59)
Caused: java.io.IOException: Unexpected termination of the channel
	at hudson.remoting.SynchronousCommandTransport$ReaderThread.run(SynchronousCommandTransport.java:73)

[landauf]

Apparently since Jenkins version 2.54 Java 8 is required to run the slave (see ​https://issues.jenkins-ci.org/browse/JENKINS-27624).

I changed the Dockerfile of the build-image to install Java 8: r11434

Now it seems to work again.