ACCESS MODIFIERS

Access Modifiers:

public – accessible within the class, within the same package and outside the package.

protected – accessible within the class, within the same package. It is accessible outside the package, but only to the class that is a subclass. Also it will be accessible only on the object of child, still not accessible on the object of Parent.

default -  accessible within the same class and within the same package. Not accessible outside the package.

private – accessible only within the same class.

Let us review these access modifier by taking and example of ATM.

We will make 2 packages with atleast 1 class in each of them.

package mybank.atm;

public class Atm

{

            public String bankName;

            public String location;

            String policeContactNo;

private cashInAtm;

public float withdrawMoney(String cardNo)

{

            // anybody should be able to withdraw money

}

protected void getDaysTransaction(String cardNo)

{

            // should be available t

}

           

           

private getTotalCashInAtm()

            {

                        // no one needs to know what is the total cash in ATM

            }

            void callPolice()

{

// bank can make an automated call to police if somebody tries to vandalize the ATM

// the security guard can also make a call to police if suspects any robbery at ATM

}

}

package mybank.customer;

public class Customer

{

            public String customerName;

            public static void main(String args[])

            {

                        Atm atm = new Atm();

            atm.withdrawMoney(“”);

                        atm.callPolice(); // will give compilation error

            atm.getTotalCashInAtm(); // will give compilation error

}

}

package mybank.atm;

public class SecurityGuard

{

            public String guardName;

            public static void main(String args[])

            {

                        Atm atm = new Atm();

            atm.withdrawMoney();

                        atm.callPolice();

            atm.getTotalCashInAtm(); // will give compilation error

}

}