An aditional detail: when I start the JBoss AS's standalone.sh script through linux terminal, the server is not early terminated. That only happens when the server is started through JBDS.
No, I haven;t seen such behavior - have my AS 7's running for hours/days via jboss tools/JBDS.
exit 143 normally means some other process or the process it self decided to kill it...
I found out what's the problem. I experimented running JBoss AS 7 with jdk7 through JBDS in 2 platforms, Mac OS X and Linux, and both presented the issue described previously by me. When running in the same way on Windows Seven (with Oracle JDK7) everything worked fine.
So I guess the issue is between JBoss Tools and openjdk7.
By now I'm returning to openjdk6.