RE: Class Loading Question

From:

Vincent van Beveren <vvanbeveren@xiam.nl>

Newsgroups:

comp.lang.java.programmer

Date:

Thu, 27 Jul 2006 09:06:12 +0200

Message-ID:

<ea9ol9$j7i$1@azure.qinip.net>

Hal Vaughan schreef:

When the program is run as an applet, I know MyClass has to be available,
but will it also be loaded? If so, is there a way to get around it and not
load classes unless the program actually calls them?

Hi Hal,

The jar file(s) you specify at in the archive attribute are always
loaded prior to the application start up. The only thing you might be
able to do is use an java.net.URLClassLoader to load specific modules.
For example:

private Runnable clientModule;

void enterClient() {

   if (clientModule == null) {
     // maybe display message 'please wait loading module'
     URLClassLoader urlc = URLClassLoader.getInstance(
       "clientModule.jar", getClass().getClassLoader());
       try {
         clientModule = (Runnable)
            urlc.loadClass("my.package.ClientModule")
            .newInstance();
       } catch (Exception e) {
          // better exception handling
       }
    }

    clientModule.run();

}

Something like that. You might have some security issues though.

Vincent