How to prevent duplicate servlet jar using eclipse+m2eclipse

Question

I\'m using Eclipse + Maven + m2eclipse to build and test a web application in Apache Tomcat.

I\'ve configured a Tomcat server inside Eclipse, and configured the depl

Answer 1

Install extras for m2eclipse plugin ("Maven Integration for WTP") from update site http://m2eclipse.sonatype.org/sites/m2e-extras. After install, update the project configuration.

Answer 2

Normally there is a dependency in your project that is depending on servlet-apî.jar

The default behaviour of Maven is that i wiill try to import your dependency + the dependencies of the imported dependency.

If you want to exclude a specific "sub-dependency", you can give maven a configuration like this :

<dependency>
    <groupId>com.hpsworldwide.mbtrs.switch</groupId>
    <artifactId>YOUR_DEPENDENCY</artifactId>
    <version>1.0</version>
    <exclusions>
        <exclusion>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
        </exclusion>
    </exclusions>
</dependency>

then maven will import YOUR_DEPENDENCY + all YOUR_DEPENDENCY dependencies, but will exclude servlet-api from the dependencies of YOUR_DEPENDENCY.

Answer 3

I have just had a similar problem, and believe I have got to the bottom of it.

If you go to your server configuration settings in Eclipse and select "Serve Modules without Publishing" then this should no longer occur.

Maven/M2Eclipse is building the WAR correctly - servlet-api-2.5.jar wont be in your target directories or WAR file.

But the problem is, when you deploy the application via eclipse on to your tomcat, Eclipse does not use your maven built WAR/target directories as default, it just uses the normal Eclipse "export" settings for your project. So it sees in your "Java EE Modules" (or "Deployment Assembly List" if you are using Helios) the list of all the jars in your Maven_Dependencies, but it does not respect the scope, and just deploys all the jars.

If you select serve without publishing option then Eclipst/Tomcat should just run the app straight off your target directory so will respect the maven scopes.

It won't ever affect your live deployments (unless you are deploying via eclipse!) as maven is doing the right thing, but it can sometimes cause problems locally as you can ave conflicting servlet/jsp jars which can cause classcastexceptions and general misery...

Answer 4

One tip: after install "Maven Integration for WTP" and update the project configuration, check the directory /WEB-INF/lib and delete all JARs inside. Now, clean the Tomcat work dir and run again.

Answer 5

If you are using Indigo you can find the WTP plugin by clicking to "Window" -> "Preferences" -> "Maven" -> "Discovery" -> "Open Catalog".