If you are doing java in LDD you always need to save design elements after you update your source code. It is so painful (at least for me) because each time I need to check result I have to switch from source window to design window and do save there.
To avoid that - set this option you see on screen below (I believe at some point IBM will set as default)
To avoid that - set this option you see on screen below (I believe at some point IBM will set as default)