what is the use of static keyword in main() 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: 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