중복 Class가 포함된 Jar 파일 찾는 방법

(SGWT Pro or better) I have odd errors that seem to imply duplicate .jars or old .jars are around

The WizTools classloader-servlet is very useful for troubleshooting such issues. 

To install, download classloader-servlet-1.0-SNAPSHOT.jar to WEB-INF/lib/ and add this to your web.xml:

Code:

    <listener>
        <listener-class>org.wiztools.classloaderservlet.ClassloaderServletListener</listener-class> 
    </listener>
    <servlet>
        <servlet-name>ClasspathListingServlet</servlet-name>
        <servlet-class>org.wiztools.classloaderservlet.ClasspathListingServlet</servlet-class>
    </servlet>
    <servlet>
        <servlet-name>DisplayClassSourceServlet</servlet-name>
        <servlet-class>org.wiztools.classloaderservlet.DisplayClassSourceServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>ClasspathListingServlet</servlet-name>
        <url-pattern>/ctx/list-classpath</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>DisplayClassSourceServlet</servlet-name>
        <url-pattern>/ctx/class-source</url-pattern>
    </servlet-mapping>

Then redeploy your app - if your app is deployed at http://localhost:8080, then visit:

http://localhost:8080/ctx/list-classpath

http://localhost:8080/ctx/class-source?class=some.class.with.Issues

This will reveal if the class in question has been loaded from multiple copies of the same .jar, including the exact filesystem path to the JAR containing the class.