Question

try {
  MyClass[] myClass = cProxy.getMyClass();
  return "" + myClass[0];
} catch (Exception e) {
  // nothing to do
}
return "" + MyClass.UNKNOWN; <-- NoClassDefFoundError thrown

I got MyClass object from other objects, I just wondering why instead of line

MyClass[] myClass = cProxy.getMyClass();

did the Exception throw when called the static variables “MyClass.UNKNOWN” of MyClass class?

What’s the deep meaning of NoClassDefFoundError and ClassNotFoundException? Thanks

Answer 1

Here are excerpt from java Docs about both the exceptions.

NoClassDefFoundError:
Thrown if the Java Virtual Machine or a ClassLoader instance tries to load in the definition of a class (as part of a normal method call or as part of creating a new instance using the new expression) and no definition of the class could be found.
The searched-for class definition existed when the currently executing class was compiled, but the definition can no longer be found.

ClassNotFoundException :
Thrown when an application tries to load in a class through its string name using:
• The forName method in class Class.
• The findSystemClass method in class ClassLoader .
• The loadClass method in class ClassLoader.
but no definition for the class with the specified name could be found.