java.lang.IllegalAccessError: tried to access method

by

This happens when accessing a package scoped method of a class that is in the same package but is in a different jar and classloader.

This was my source, but the link is now broken. Following is full text from google cache:

Packages (as in package access) are scoped per ClassLoader.

You state that the parent ClassLoader loads the interface and the child
ClassLoader loads the implementation. This won’t work because of the
ClassLoader-specific nature of package scoping. The interface isn’t visible to
the implementation class because, even though it’s the same package name,
they’re in different ClassLoaders.

I only skimmed the posts in this thread, but I think you’ve already discovered
that this will work if you declare the interface to be public. It would also
work to have both interface and implementation loaded by the same ClassLoader.

Really, if you expect arbitrary folks to implement the interface (which you
apparently do if the implementation is being loaded by a different
ClassLoader), then you should make the interface public.

The ClassLoader-scoping of package scope (which applies to accessing package
methods, variables, etc.) is similar to the general ClassLoader-scoping of
class names. For example, I can define two classes, both named com.foo.Bar,
with entirely different implementation code if I define them in separate
ClassLoaders.

Joel

More Related Contents:

  1. I am new in using ArrayLists. Array Out of Bounds, Array seems to be empty, but have been adding Strings to it already
  2. When to choose checked and unchecked exceptions
  3. How can I read a text file in Android?
  4. What is an OutOfMemoryError and how do I debug and fix it
  5. Handling exceptions from Java ExecutorService tasks
  6. Java unreported exception
  7. In Java, when should I create a checked exception, and when should it be a runtime exception? [duplicate]
  8. Why doesn’t Java allow generic subclasses of Throwable?
  9. How do you assert that a certain exception is thrown in JUnit tests?
  10. How do I increase the number of displayed lines of a Java stack trace dump?
  11. Handling Java crypto exceptions
  12. JDBC driver throws “ResultSet Closed” exception on empty ResultSet
  13. What is difference between Errors and Exceptions? [duplicate]
  14. java.net.MalformedURLException: no protocol
  15. org.hibernate.MappingException: Unknown entity: annotations.Users
  16. How can I throw a general exception in Java?
  17. PKIX path building failed in Java application
  18. javax.crypto.BadPaddingException
  19. How can I detect when an Exception’s been thrown globally in Java?
  20. Exception without stack trace in Java
  21. String index out of bounds exception java
  22. Catching an exception that is nested into another exception
  23. Java InputMismatchException
  24. How can I catch all exceptions thrown through reading / writing a file?
  25. Print the stack trace of an exception
  26. Try-catch-finally and then again a try catch
  27. In Java, what is the difference between catch a generic exception and a specific exception (eg. IOException?)
  28. problems with java3D lib configuration
  29. Why does a Java Lambda which throws a Runtime Exception require brackets?
  30. Java 8 Supplier Exception handling with CompletableFuture

Leave a Comment