For information, there seems to be a bug in the context object.
There are two ways to modify a context variable from a tJava :
context.new1 = "TOTO";
In this first case, tContextDump does not seem to take into account the change of the value of new1. (restores the initial value of new1 at the beginning of the job)
context.setProperty( "new1", "TOTO" );
However, the tcontextDump component works with this second solution!
(Test in TOS version 7.0.1)