Swap methods

Recursive functions

Getter functions

Setter functions

To enable reusability

To enable polymorphism

To execute java code

To separate block of code

[access modifier] return_type  function-name(parameter-list){}

[access specifier] return_type  function-name(parameter-list){}

[access modifier] return_type  function-name(parameter-list){}

[access specifier] [modifier] return_type  function-name(parameter-list){}