What methods can be used to declare an integer variable that can accept null value?

In Java, a variable of type int cannot accept the value null because it is a primitive type. To allow an integer type variable to accept null, you need to use the wrapper class Integer.

Example declaration:

Integer number = null; // allows null
int primitiveNumber; // does not allow null

Therefore, for a variable that allows null, use the wrapper class Integer instead of the primitive int.