Static Methods and Variables

-Can be accessed at class level

-Does not require Class instance (aka Object) 

-Static variable keeps only one value during entire program execution,
 unlike Instance variable, which maintains separate values (state) per instance (Object) 

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Example: To demonstrate Static and Instance variables and methods

public class AccountHandler {

     public static double MAX_DEPOSIT_LIMIT = 1000000;         

     //Instance method to deposit specified amount to specified customer Id

     public void doDeposit(String customerId, double amount) {

          if (amount > MAX_DEPOSIT_LIMIT) {

               System.out.println("Can not process, exceeding limits, Amount: " + amount);

               return; //return to caller

          }

          System.out.println("Depositing amount " + amount + " for Customer Id : " + customerId);

     }

     //Static method to show customer's ß for the specified customer Id

     public static void showPortfolio(String customerId) {

          System.out.println("Showing Portfolio for Customer Id : " + customerId);

     }

}
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public class TestStatic {

    public static void main(String[] args) {

          //check account deposit limits by accessing static MAX_DEPOSIT_LIMIT

          System.out.println("Allowable deposit limit : " + AccountHandler.MAX_DEPOSIT_LIMIT);

          AccountHandler handler = new AccountHandler();

          //calling instance method by using dot operator on instance of AccountHandler class

          handler.doDeposit("a007", 10000);

          //calling static method by using dot operator on AccountHandler class

          AccountHandler.showPortfolio("a007");

     }

}