Hitting a Java breakpoint causes X11 to freeze

September 29, 2014

This is an annoying problem that I would come across from time to time.

When debugging a Java application on Linux (Mint 11) using Eclipse, on hitting a breakpoint the whole system would appear to freeze.

I found I could drop down to a shell with CTRL+ALT+F1, login then use list the running processes and grep for any java processes and kill the relevant process.

simon@simon-mint-vm ~ $ps -ely | grep java
S  1000  2374  2373  6  80   0 442072 297255 futex_ ?      00:01:57 java
S  1000  3216  2374  0  80   0 86264 1442616 futex_ ?      00:00:08 java
simon@simon-mint-vm ~ $ kill -9 3216

Then return to the X session with CTRL+ALT+F7 and the screen would be unfrozen.

After having to do this numerous times I managed to find a solution on the internet; when starting the jvm give it the option -Dsun.awt.disablegrab=true

In Eclipse you would enter this in the ‘VM arguments’ pane in the ‘Debug Configrations’ dialogue.

I believe this to be a JVM problem rather than anything to with Eclipse, I was using JRE.


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