That determines, for a given class, whether a given object is an
instance of that class.

E.g.:

final Class stringClass = String.class;
assert stringClass.isInstance("Hello World") == true;
assert stringClass.isInstance(new Integer(42)) == false;

   - Oliver

usually used in the shorthand syntax

       if ( o instanceof MyClass)
       // stuff

which returns true if o is an instance of MyClass or some subclass of
MyClass. This isn't what you want, because

(i) o may be an instance of some class which is unrelated to MyClass and
still not be null, and

(ii) o instanceof java.lang.Class would throw a runtime exception (actually
a NullPointerException) if o was null.

Of course instead of

       if ( o != null)
       {
               // stuff
       }

you could equally use

       try
       {
               if ( o instanceof Class)
               {
                       // stuff
               }
       }
       catch ( NullPointerException npe)
       {
               // ignore
       }

but I think you'll agree that would be woefully over complex, and would
make it problematic to debug actual null pointer exceptions which happened
in your code.