Introduction to Programming

toString()

There are cases when you need to convert an object (which is a reference to some class type) to its String representation. When the reference obj is assigned a null value (the object is not created yet), writing obj.toString()  generates NullPointerException. For such cases, using the following methods of the class Objects is a better choice:

• String toString(Object o): returns the result of calling toString() on the first parameter when it is not null and null when the first parameter value is null
• String toString(Object o, String nullDefault): returns the result of calling toString() on the first parameter when it is not null and the second parameter value nullDefault when the first parameter value is null

Here is the code that ...