From which Jar a Class was loaded?

Posted by Paolo Dona' Sun, 13 Nov 2005 15:11:00 GMT

Sometimes in production environments I face problems never encountered during development… It’s a general thing.. could happen with jdbc drivers or xml parsers.

I just feel classes are loaded from a different jar than expected.

This of course could happen if you’re deploying to a very different application server or if you’ve no control over the production server classpath.

I found in javaalmanac.com a code snippet that can help you identify which is the jar containing a specific Class at runtime:

Class cls = MyFoo.class;
ProtectionDomain pDomain = cls.getProtectionDomain();
CodeSource cSource = pDomain.getCodeSource();
URL loc = cSource.getLocation(); 
System.out.println(loc); 
// prints something like "c:/jars/MyFoo.jar"

This way you can check if your class is loaded right from the expected jar, not elsewhere :-).

This has shown to be really useful during my sad production debug sessions.

Hope it can help you as well.

Tags class, classloader, jar, java | 13 comments

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jug-33 said 30 days later:

Perchè ci sono 4 pagine in italiano ed una inglese.

I commenti li devo scrivere in Inglese o in Italiano. Per me sarebbe più semplice scrivere in italiano ma se mi ritrovo in un forum inglese scrivo in inglese , ma se il forum è italiano e si spaccia per inglese scrivo in italiano .

Insomma inglese o tutto o niente (compresi i commenti)
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Lucio said 32 days later:

The forum doesn’t pretend to be english. Simply we would like all people could read contents, even english people.

Write as you want, italian or english, but if the post is i english, it would be polite to comment in english.
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jug-33 said 34 days later:

hi there,

I’m not a jug’s member but this is my thought.

The developer must be to know the english, because all the documentation in the world is in english language and if we want to make grow the community and to go around the world write in english , yeh yeh of course sometimes we can mistake the grammer and we could to make a shit scenarious … but only the man without fear can to speak with god.
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Bert said 331 days later:

Thx, this helped.
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Benoit Moussaud said 782 days later:

Very Useful, thanks !
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Egor said 1155 days later:

You are the man! Saved my day.
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watches mens said 2003 days later:

The developer must be to know the english, because all the documentation in the world is in english language and if we want to make grow the community and to go around the world write in english , yeh yeh of course sometimes we can mistake the grammer and we could to make a shit scenarious … but only the man without fear can to speak with god.
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