You should call the toString method by using invoke4 predicate:
JIP:-create_object('java.lang.String'('java.lang.String'), ['Hello World'], Handle).
Yes
Handle = #-
862545276
JIP:-invoke('#-862545276', toString, [], RetVal), get('java.lang.System', out, Out), invoke(Out, println('java.lang.Object'), ['#-862545276'], A).
Yes
RetVal = Hello World
Out = #6808118
A = []