How to deal with classpath conflict

Question

In my project, I'm using both glassfish-embedded 3.1.1 and the guava lib... The problem is that glassfish comes with the old implementation of guava (ie google-collections)...

This results in NoSuchMethodError at runtime, for example when using Lists.reverse(), or Sets.newIdentityHashSet() which were introduced later in guava.

I don't find any solution to solve this... (the only one is to manually trash the com/google classes directory in the glassfish jar...)

In case you care, I found an embedded v4 build and the classpath issue went away. You can find the build here: http://grepcode.com/snapshot/maven.java.net/content/groups/promoted/org.glassfish.main.extras/glassfish-embedded-all/4.0.1-b01 — JagWire, Feb 20 '14 at 21:21
@JagWire I'm not working with Glassfish anymore, but it's a very good thing to know they have fix this. I will update Kevin's anwser with your link. Thanks a lot for that :) — sly7_7, Feb 21 '14 at 14:34
I have a similar problem, not with glassfish, but with some other jar library from my poms. Unfortunately I have a lot of libraries in my poms. Can someone tell me how to track down which jar is causing a conflict? I have no idea how to do it. All I know is my code crashes when I try to edit my guava in my poms to higher than 19.0 - and I want to use functionality from 21 in my project! but can't as long as this problem persists... — ycomp, Jun 01 '17 at 05:36

score 7 · Answer 1 · edited May 23 '17 at 12:14

7

You can overcome this be specifying the below. Read the Delegation section of the Class Loaders chapter.

<class-loader delegate="false" />

Check this SO post for class loading in Java EE apps in general: Java EE class loading standard

edited May 23 '17 at 12:14

Community

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answered Sep 30 '11 at 16:19

Aravind Yarram

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We try it, but it does not work in our case... This results in ClassCastException (probably due to same classes loaded by different classloaders) – sly7_7 Oct 03 '11 at 08:22

score 4 · Accepted Answer · edited Feb 21 '14 at 14:39

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Glassfish should never have included com.google classes in their own jar. That was an error.

UPDATE[@sly7_7]: It seems like glassfish does not include guava in their own jar anymore, but it depends on the guava artifact instead. This should resolve the problem. Thanks to @JagWire for pointing this.

edited Feb 21 '14 at 14:39

sly7_7

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answered Oct 01 '11 at 01:42

Kevin Bourrillion

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That's what I think... and it's the same thing for slf4j :( – sly7_7 Oct 02 '11 at 21:57

score 0 · Answer 3 · answered Feb 20 '14 at 21:23

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I was able to make the error go away by using the following Glassfish v4 build:

http://grepcode.com/snapshot/maven.java.net/content/groups/promoted/org.glassfish.main.extras/glassfish-embedded-all/4.0.1-b01

Might be worth taking a look.

answered Feb 20 '14 at 21:23

JagWire

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How to deal with classpath conflict

3 Answers3