[news.eclipse.newcomer] Re: Loading jars dynamic from plugins

[pm@xxxxxxxxx (Franz Philipp Moser)]

Walter Harley wrote:

> "Franz Philipp Moser" <pm@xxxxxxxxx> wrote in message 
> news:dcb02f1d56d6d9f961e57d6dc824e96b$1@xxxxxxxxxxxxxxxxxx
> > can I load eclipse with adding some jars to the classpath? This would help 
> > a lot!

> Do you mean, can you add jars to the classpath that you use to launch 
> Eclipse with, and then expect the classes in those jars to be visible to 
> plug-ins?  In general, no, I don't think so; and you shouldn't, anyway.

> Eclipse is a modular application platform.  (It's also an IDE built on top 
> of that modular application platform.)  The thing that makes it modular is 
> that there are strict boundaries placed on how classes in different modules 
> can interact with each other.  Those boundaries are defined by the OSGi 
> spec, which Eclipse implements.  So the whole point here is that Eclipse is 
> what it is, and is able to do what it does, precisely *because* of these 
> limitations.  Making classes visible to all plug-ins is sort of like putting 
> all of your classes in the same package and declaring all your methods and 
> fields to be public: sure, it makes coding easier in the short term, but it 
> makes the code unmanageable as the application grows.

Ok, thats clear and I begin to see eclipse goes an other way than java 
normaly goes. I always liked the way of adding jars (and therefor classes 
I need) with the classpath to my app or create a classloader like this.

loader = new URLClassLoader(urls);

urls has the jars found in a specified directory that can be configured by 
the enduser.

> What exactly is it that you are trying to do?  Is there some reason that 
> createExecutableExtension() is not a good answer for you?

for example I wan't to "drop in" jdbc drivers, that will be used by the 
core app loading them the "normal" way with 
Class.forName("com.mysql.jdbc.Driver"). I don't know witch driver the end 
user will use so it can be configured and added by installing the right 
plugin.

I thought this is the right way, but maybe eclipse has an other right way?

Thanks for your help by now, I see things clearer now and try to think the 
eclipse way ;)