private constructor [duplicate]

Question

Possible Duplicate:
What is the use of making constructor private in a class?

Where do we need private constructor? How can we instantiate a class having private constructor?

Answer 1

One common use is in the singleton pattern where you want only one instance of the class to exist. In that case, you can provide a static method which does the instantiation of the object. This way the number of objects instantiated of a particular class can be controlled.