Exception in thread "main" java.lang.NoClassDefFoundError: org/joda/time/ReadableInstant

Question

I built an executable jar using an ant script, the only external jar I used was joda-time 2.0. The ant build script "seemed" to work as I did not recieve any compile errors, and if I were to remove the jode-time 2.0.jar from the lib directory the build would indeed fail as expected. At any rate, after building the jar I get this error when I try to run with:

java -jar myapp.jar

Exception in thread "main" java.lang.NoClassDefFoundError: org/joda/time/ReadableInstant

Any thoughts on this? I'm just not sure where to look, everything works just fine within Eclipse. thanks for any ideas

Answer 1

Presumably, your jar doesn't contain a manifest header telling Java to add the joda-time jar to the classpath. That's the only way to have other classpath entries when using java -jar. You could do this directly with the Ant manifest task, or there are probably multiple other ways to do it, including building it from your existing classpath.

Alternately, try

java -cp myapp.jar:joda-time-2.0.jar com.foo.YourMainClass

Answer 2

Unless you're using a custom classloader or something like JarJar, then you cannot bundle external JARs inside your executable JAR. Your manifest file will need to list a classpath, but the JVM will look for the JARs you list in the same directory as your executable JAR, not inside your executable JAR.