So the situation is like this: We have an application that relies on a jar file. This jar file is our customization to the W3C flute project. Let's call this jar flute1.jar. Our app has a bug that necessitates fiddling with flute1.jar.

So I located the bug. I rebuilt the flute1 project. I installed the newly built flute1.jar into our app. And then I committed the newly built jar (replacing the old jar) into the svn repo.

Our Hudson threw this message:

    [javac] bad class
    [javac] class file has wrong version 50.0, should be 48.0
    [javac] Please remove or make sure it appears in the correct subdirectory of the classpath.
    [javac] import org.w3c.flute.parser.Parser;
    [javac]                             ^
    [javac] 1 error





What has gone wrong? It turned out that I built the flute1.jar to conform to Java 1.5 while our app conformed to Java 1.4 only. So I added the target="1.4" switch to the javac task in my ant build file. And it worked.