Server doesn't always save world on SIGTERM

Sending SIGTERM to minecraft server doesn't always properly shutdown.

Sometimes when I send SIGTERM it appears to shutdown properly like so.

2013-06-04 00:37:53 [INFO] Closing listening thread
2013-06-04 00:37:53 [INFO] Saving players
2013-06-04 00:37:53 [INFO] Saving worlds
2013-06-04 00:37:53 [INFO] Saving chunks for level 'world'/Overworld

Other times I only see

java.net.SocketException: Socket closed
at java.net.PlainSocketImpl.socketAccept(Native Method)
at java.net.AbstractPlainSocketImpl.accept(AbstractPlainSocketImpl.java:398)
at java.net.ServerSocket.implAccept(ServerSocket.java:522)
at java.net.ServerSocket.accept(ServerSocket.java:490)
at if.run(SourceFile:61)

So I am unaware if the world was properly saved in these cases.

It would also be nice if other common signals were supported, for example HUP and SIGUSR2.