Class not found error although jar is included - and now?

I run a script that loads a java class in a script library and get the following error although I included all the dependend jars (and the java script library compiles without a problem). What can I do to get this fixed?The java console does not open (seems to be an error in 8.5.1) so I had to use the script to retrieve the error :

JavaError encountered: java.lang.NoClassDefFoundError: org.springframework.jms.JmsException

Stacktrace:

java.lang.NoClassDefFoundError: org.springframework.jms.JmsException

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

at java.lang.ClassLoader.defineClass(ClassLoader.java:265)

at java.lang.ClassLoader.defineClass(ClassLoader.java:202)

at lotus.domino.JavaConnectLoader.findClass(Unknown Source)

at java.lang.ClassLoader.loadClass(ClassLoader.java:643)

at java.lang.ClassLoader.loadClass(ClassLoader.java:609)

at lotus.domino.JavaConnectLoader.loadClass(Unknown Source)

at java.lang.J9VMInternals.verifyImpl(Native Method)

at java.lang.J9VMInternals.verify(J9VMInternals.java:72)

at java.lang.J9VMInternals.initialize(J9VMInternals.java:134)

Caused by: java.lang.ClassNotFoundException: org.springframework.jms.JmsException

at lotus.domino.JavaConnectLoader.findClass(Unknown Source)

at java.lang.ClassLoader.loadClass(ClassLoader.java:643)

at java.lang.ClassLoader.loadClass(ClassLoader.java:609)

at lotus.domino.JavaConnectLoader.loadClass(Unknown Source)

... 10 more