Are native screen resources automatically released when the JVM exits?

Question

If doing System.exit(1) from a Swing application, are native resources related to the graphics automatically released ? If I add a myFrame.dispose() with myFrame being the sole top-level container in the app, can I be sure not to get the annoying behavoiur seen in some non-java GUI using programs where part of the GUI state will stick frozen to the screen when exiting abruptly ?

Answer 1

Everything owned by a process is released when the process exits, unless you are talking about pathological operating systems like Netware 3 & 4.

Answer 2

• Top-Level Containers never GC'ed, because missed method finalize()

• In this context JFrame.dispose() do nothing, this container is still present in UsedMemory, un_changed, untill current JVM instance exits,

• you can returns UsedMemerory by removing it contents, notice remove anything from ContentPane, otherwise (RootPane removed) your container stays translucent, only with visible ToolBar and Borders,

• all Window are always accesible and re_usable, you can test that by Window[] allWindows = Window.getWindows(); throught whole application lifecycle

• before re_using test container for isDisplayable()

• everything important here

then

1) don't create lots of Top-Level containers,

2) re_use container that exist

3) only Object that lost all referencies could be GC'ed