The JVM feature that would improve my productivity the most: unlimited Hot Swap
I develop IntelliJ IDEA plugins and web applications. I must see “Can’t reload classes: add method not supported” 20 times per day. Then I shut down, wait 2 minutes for IDEA or Tomcat to start in debug mode, and continue debugging. I think I could get twice as much done in a day if I didn’t have to do this. I know there’s a bug in the Sun database but I can’t find it. The Sun issue report for this problem is 4910812.
Are you a slave to hot swap? Do you avoid renaming, extracting, or changing modifiers of methods so you can reload the classes? How do you get around it?
August 26th, 2005 at 5:14 pm
w.r.t. tomcat, why not just redeploy your war?
August 27th, 2005 at 5:36 am
Or you can try Jetty, which take much much less time to restart
September 3rd, 2005 at 11:31 pm
Is it this one? http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4910812
October 6th, 2005 at 1:02 pm
Bob Lee and I have been searching for a JVM that might do this, or _something_. Lately we’ve given up that Sun is interested in solving this, and instead started to look at writing some crazy classloader that could emulate this for you by recompiling objects, tracking references to objects, and using reflection to copy over changes. Not sure how possible it is.
This is exactly what I was trying to solve with WebWork’s “prototype” feature — it works great until lame libraries (read: Hibernate) hold on to objects/class definitions longer than they should. Then it’s game over: time to restart your app.
To those who think reloading the webapp is an option — heh, you’ll sing a diffirent tune as soon as you have to deal with an app that takes a long time to start up (for whatever valid or invalid reason).
October 11th, 2005 at 8:23 am
PLEASE VOTE: the only JVM bug you’ll ever really care about
If there was only one bug/feature request everyone should care about, this. The expansion of HotSwap support is required for Java to stay cutting edge. Java will get passed up if it continues to require that entire web apps be…
March 12th, 2006 at 11:26 am
I think IBM’s J9 JVMs fair a little better. I could be wrong though
March 27th, 2006 at 12:59 pm
Please vote for this java bug
Please vote for this java bug: http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4910812
This is related to the hotswap feature of java vm.