How to prevent jar-in-jar-loader loading specific class?

Question

Imagine I have a following project structure of folders

• A
• B
• C

and many external jars.

Now I am trying to build two different executable-jars like this A+B, A+C.

At first, I do Eclipse -> Export -> Executable Jar and save script for Ant. So it generates Ant-script and jar-in-jar-loader. Now I modify ant script to exclude folder B

    <fileset dir="C:/Users/Nikolay/bin">
        <exclude name="org/B"/>
    </fileset>

and keep jar-in-jar-loader.zip file unmodified.

After building the jar running gives this error:

    Exception in thread "main" java.lang.NoClassDefFoundError: org/B
        at java.lang.Class.forName0(Native Method)
        at java.lang.Class.forName(Class.java:264)
        at org.eclipse.jdt.internal.jarinjarloader.JarRsrcLoader.main(JarRsrcLoa
der.java:56)
Caused by: java.lang.ClassNotFoundException: org.B
        at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
        ... 3 more

But I am sure B class is not used in the A.

It seems like JarRscrLoader tries to load all listed classes at application startup. How can I prevent that?

Please, don't suggest me to split the code at Eclipse into 2-3 projects.

Answer 1

Create two different Run configurations (Run --> Run configurations...) and modify the included libraries in the classpath tab according to your requirements.

When you export the project, just select the appropriate configuration.