WHY DO WE USE static code example

Example 1: static in java

static keyword is a non-access modifier. static keyword can be used with 
class level variable, block, method and inner class or nested class.

Example 2: do i have to use static methods in java main

Use a static method 
when you want to be able to access the method 
without an instance of the class

Example 3: static in java

The static keyword in Java is used for memory management mainly. We can apply static keyword with
variables, methods, blocks and nested classes. The static keyword belongs to the class 
  than an instance of the class.

The static can be:

Variable (also known as a class variable)
Method (also known as a class method)
Block
Nested class