Java error: Found interface … but class was expected

Question

I am getting a strange runtime error from my code:

\"Found interface [SomeInterface] but class was expected\"

How can this happen? How can an i

Answer 1

This happens when your runtime classpath is different than your compile time classpath.

When your application was compiled, a class (named SomeInterface in your question) existed as a class.

When your application is running at compile time, SomeInterface exists as an interface (instead of a class.)

This causes an IncompatibleClassChangeError to be thrown at runtime.

This is a common occurence if you had a different version of a jar file on the compile time classpath than on the runtime classpath.