when i should use static java code example

Example 1: java what is static

In the Java programming language, the keyword static indicates that the particular member belongs to a type itself,
rather than to an instance of that type.
This means that only one instance of that static member is created which is shared across all instances of the 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