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javaeclipseclassjarimport

Java: Two jars in project with same class.

I have a java project that is using two imported jars with the same class (com.sun.mail.imap.IMAPFolder). Is there a way to explicitly say which jar to use when importing the class? Using: 

import com.sun.mail.imap.IMAPFolder;

would seem to use the class in order of build path order but this does not seem to be the case for some reason causing 

Exception in thread "main" java.lang.reflect.InvocationTargetException
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:616)
        at org.eclipse.jdt.internal.jarinjarloader.JarRsrcLoader.main(JarRsrcLoader.java:58)
Caused by: java.lang.NoSuchMethodError: com.sun.mail.imap.IMAPFolder.idle()V
        at com.woodbury.GCM.HelperGmailMonitor.doEmail(HelperGmailMonitor.java:104)
        at com.woodbury.GCM.Launch.listen(Launch.java:16)
        at com.woodbury.GCM.Launch.main(Launch.java:10)
        ... 5 more

at runtime. I am building the project in eclipse.

Solution

  • You cannot do what you ask just in your Java source. Java was not designed for that.

    This is a bad situation which can only be handled reliably with custom class loaders, each providing one of the jars you need. Since you are asking this question in the first place this is probably not the way you should go yet since that opens up a LOT of new time consuming problems.

    I would strongly suggest you find out why you have two different versions of the same jar in your classpath and rework your program so you only need one version.