Difference : Overloading and Overriding

Argument(s)
Overloaded Method : Must change.
Must not change.

Return type
Overloaded Method :Can change.
Overridden Method :Can't change except for covariant returns.

Exceptions
Overloaded Method :Can change.
Overridden Method :Can reduce or climinate. Must not throw new or broader checked exceptions.

Access
Overloaded Method :Can change.
Overridden Method :Must not make more restrictive (can be less restrictive).

Invocation
Overloaded Method :Reference type determines which overloaded version (based on declared argument types) is selected. Happens at compile time. The actual method that's invoked is still a virtual method invocation that happens at runtime, but the compiler will already know the signature of the method to be invoked. So at runtime, the argument match will already have been nailed down, just not the class in which the method lives.
Overridden Method :Object type (in other words, the type of the actual instance on the heap) determines which method is selected. Happens at runtime.