JDK version problem

Question

I am looking for clarification in jdk versions.

I am getting error

java.lang.UnsupportedClassVersionError:Bad version number in .class file"

I hope this error is for different jdk version. I am having myeclipse6.0.1 and weblogic10.3.

Now, in my systems has jdk1.5 but weblogic has jdk1.6, as well myeclipse supporting 1.5 only.

I read the all forums and they said compile is different version and running different version.

So, here i thought program compliling 1.5 and running 1.6.

Is it correct ?

• rose: this error getting when running the project.it was deploying successfully.

Answer 1

This means that the Java program was compiled for a newer version of Java than you are trying to run it with.

The easiest way to be certain is to use the same version of Java for compiling and building as is to be used on the final system. For you, this is most likely Java 5.

• Stewart Murrie: Apparently it's possible to get a Java 6 compiler to generate bytecode for Java 5, but I could never get it to work properly. It ended up being easier just to get a Java 5 compiler.
• Andrew Thompson: It certainly is possible. But for it to work reliably(1), you need to use the -bootclasspath option of javac, which requires an rt.jar (not a JDK) of the target version. (1) As well as specifying -source/-target.
• Thorbjørn Ravn Andersen: @britishmutt, it is possible, but even with byte codes being correct, you are still compiling against a newer version of the runtime library, and subtle differences exist. For Hudson we use the Eclipse compiler with ant running under the appropriate JRE.
• Stewart Murrie: @AT, TRA: Yep, that's what I was meaning. It's a bit of rabbit hole to get cross-compilation working correctly.