Hi all,
One can start the JVM with the option of putting itself into debug mode if an uncaught exception is thrown.
Do you know whether it's possible to explicitely put the JVM into debug mode without throwing an exception. Say I have a Java program with a UI and I want to have a command in the UI that puts the program (JVM) in debug mode.
Thanks,
Boris
Thanks for your response, but this is not really what I'm looking for. This is simply "debugging" as opposed to "just-in-time debugging" ;)
I would like to be able to start the JVM in normal mode - not in debug mode - and eventually, after having it run for some time like this, switch to debug mode without shutting it down.
I know that this is possible for uncaught exceptions. I'm looking for a way to force it without throwing an uncaught exception.
Thanks,
Boris
I see.
I doubt that you'll be able to run a program for purposes of debugging, but also have it run at full non-debugging speeds.
The easiest thing may be to put some trace/debugging statements in your code, using this idiom:
private static final boolean DEBUGGING = true;
//...
if (DEBUGGING) {
System.err.println("current state is something " + someObject);
}
to debug the problem area of your code. If you set DEBUGGING to false later and recompile the extra statements won't be included in the final class file. Or you could make DEBUGGING non-final and change its value when an exception is thrown (or whatever) but then you'd find it hard to remove the extra statements later.
> Do you know whether it's possible to explicitely put
> the JVM into debug mode without throwing an exception.
> Say I have a Java program with a UI and I want to have
> a command in the UI that puts the program (JVM) in
> debug mode.
For all current JDI implementations, the debugee JVM must be
started with debugging enabled for you to be able to attach
later and debug. Ways to do that are described here:
http://java.sun.com/j2se/1.5.0/docs/guide/jpda/conninv.html#Invocation
The 'attach on demand' capability (where you can attach and debug
any VM, regardless of how it was started (given the appropriate access
permissions)) is the topic of Bug-IDs 4841257, 6173612, and 6173750
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4841257
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6173612
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6173570
