Hi @ahmedbasiouny , you’re right… it does cause all of KNIME to crash… lol…
so while waiting for it to reload, I found this post by @qqilihq , (who is an expert in these things).
I have pasted a screenshot of that post here, highlighting something that I think might be very important. It’s the checkbox at the bottom of the java snippet dialog. Don’t press Apply or OK without making sure that’s checked!
I’ll be giving ita try when KNIME comes back, you might wish to do so too 
(By the way, have you got ‘auto-save’ switched on? It’s definitely a good idea when living life on the edge 
)
[Edit: it now works when I try it. Hope it works for you too!]