grails test-app return code 137 I'm running grails test-app on a CI server (bamboo). And I'm getting this message:

Failing task since return code of [/opt/grails-2.4.4/bin/grails test-app unit: integration: -non-interactive] was 137 while expected 0

What specific error does 137 means? 
Btw, the result of the test-app was successful. 

Quoting answer from user @centic from this question:
Exit codes above 127 typically mean the process was stopped because of a Signal.
The exit code 137 then resolves to 128 + 9, whereas Signal 9 is SIGKILL, i.e. the process was forcefully killed. This can among others be a "kill -9 " command. However in your case this could be an out of memory condition on the operating system, which causes a functionality called "OOM Killer" to stop the process which is using up most of the memory in order to keep the OS itself stable even in such a condition.