问题
I have read a lot of answers here to NoClassDefFoundError, but somehow I could not find one that solves my problem. Maybe I have not enough experience to transform it to my problem.
Anyway, I have a project (imported over git) with a package and lots of helpful functions. There is as well a package with some demos, they work completely fine.
If I now copy one of those demos in my own project, I get the error
Exception in thread "main" java.lang.NoClassDefFoundError: org/jfree/data/xy/XYDataset at net.[...]
I think there must be a simple solution, since it runs in the other project.
Thank you for taking your time.
回答1:
NoClassDefFoundError in Java comes when Java Virtual Machine is not able to find a particular class at runtime which was available at compile time. For example, if we have a method call from a class or accessing any static member of a Class and that class is not available during run-time then JVM will throw NoClassDefFoundError.
- The class is not available in Java Classpath.
- You might be running your program using jar command and the class was not defined in manifest file's ClassPath attribute.
- Any start-up script is overriding Classpath environment variable.
- Because NoClassDefFoundError is a subclass of java.lang.LinkageError it can also come if one of its dependency like native library may not available.
- If you are working in J2EE environment than the visibility of Class among multiple Classloader can also cause java.lang.NoClassDefFoundError, see examples and scenario section for detailed discussion.
来源：https://stackoverflow.com/questions/56810860/noclassdeffounderror-by-switching-to-another-project