// generates:
// void userExprFun { }
MethodBuilder userExprFun = acb.newGeneratedFun("void", Modifier.PUBLIC);
userExprFun.addThrownException("java.lang.Exception");
methodCallBody.generate(acb, userExprFun);
userExprFun.endStatement();
userExprFun.methodReturn();
// we are done modifying userExprFun, complete it.
userExprFun.complete();