Hi Pasar,
As far as I know the JAVA stack is in maintenance mode. Existing implementations are supported, but I even think they try to actively support JAVA stack customers to move to .NET. OutSystems no longer actively tries to sell the JAVA stack. Most likely reason is that the number of JAVA stack implemenations is small compared to the .NET stack implementations and that OutSystems wants to bundle all development resources on one stack.
Regards,
Daniel.