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"The type java.util.Map$Entry cannot be resolved" (tomcat6 + JDK7)

I've a JSP app which gives me the error:

The type java.util.Map$Entry cannot be resolved. It is indirectly referenced from required .class files

Stackoverflow is full of post about this error, but all of them get to solve just compiling the .java files using JDK7, plus using tomcat with same version (I mean, below to JDK8 which seems to be the problem, because some IDE version and tomcat versions doesn't support it).

The problem is that I've built my app (.java files) using JDK 1.7.0_79, plus I've my tomcat 6 server using the same one.

So there's no JDK 8 anywhere... Some screenshots with data:

My JVM directory:

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Error stacktrace:

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Tomcat process (running using JDK7):

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Javac version used to compile:

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Any idea about why do I still get this error?

Thank you in advance

Solution

  • Run Tomcat with Java 6 or upgrade to Tomcat 7 and make sure you don't have some old pre-Java 5/pre-generics library on the classpath.

    Why do you get this error? Somewhere in the JSP code (not your code, mind), is a dependency on java.util.Map.Entry. This could be in code which Jasper generates from your JSP.

    It's not a direct dependency; rather your code (or the Java code generated from your JSP) needs something else which then needs java.util.Map.Entry

    But the interface has changed in some way. Usually, that's with Java 8 because of the new static helper methods which they added: The name of the class is the same (which makes the error so confusing) but the API has changed and the code can't find something (or found something it didn't expect).

    A similar problem can happen when you try to compile against a pre-generics class (even though that should work).

    Even worse, import java.util.Map in your JSP works. It's the existing bytecode somewhere else that causes the trouble.

    [EDIT]

    In my /WEB-INF/lib/ folder I've: commons-fileupload, commons-io, poi and rt (may this one be the problem?)

    Yes :-) rt.jar is the Java runtime. It contains java.* and in your case, a version of java.util.Map which doesn't match the one from your Java VM.

    Remote it and it should work.