Java Threads, Second Edition

NoSuchMethodError

When the Thread class was designed, certain methods were not immediately supported. To avoid changing the interface to the Thread class, most of these methods were simply written to throw the NoSuchMethodError. As more functionality has been added, fewer of these methods now throw this error condition. As of this writing, the only method that throws this error object is the destroy() method of the Thread class (see Appendix A).

Exceptions or Errors

What is the difference between an error and an exception? As far as the virtual machine is concerned, there is little difference between the two: they are simply objects that are thrown to report a condition. It is possible to catch an Error object just like an Exception object. In practice however, the usage of the two types of conditions is different.

Error conditions are faults in the Java virtual machine. In general, they are a sign of a problem that cannot be solved by the program. This can be caused by an out-of-memory condition, stack overflow, or problems in loading or resolving the classes in the program. The reason they are separated is to allow a catch-all of general exceptions. A program may catch all exception conditions by catching the Exception object, but a program should have little reason to catch an Error object.