Java Basic Programs OOPs and Exception Handling

method overriding  in java

----------------------------------
class B
{
    void test1()
    {
        System.out.println("Test-2");
    }
}
class C extends B
{
    void test1()
    {
        System.out.println("Test-2");
    }
 
    public static void main(String[] args)
    {
        C obj=new C();
        obj.test1();
 
    }
 
}

encapsulation in java

-------------------------------

class B
{
   private int a=10;
    private int b;
    private void method()
    {
        System.out.println("private msg");
    }
 
    public void  getData()
    {
        System.out.println(a);
    }
    public void setInfo(int n)
    {
        b=n;
        System.out.println(b);
    }
 
    public void getMethod()
    {
        method();
    }
 
}
class C
{
     public static void main(String[] args)
    {
        B obj=new B();
        obj.getData();
        obj.setInfo(4);
        obj.getMethod();
     
    }
 
}

abstraction  in java

--------------------------------

abstract class Shape
{
    abstract void draw();
}
class Circle extends Shape
{
    public void draw()
    {
        System.out.println("draw Circle");
    }
}
public class Rect extends Shape
{
    public void draw()
    {
        System.out.println("draw Rect");
    }
    public static void main(String[] args)
    {
        Shape re=new Rect();
        re.draw();
        Shape cir=new Circle();
        cir.draw();
    }
 
}

exception handling in java

-----------------------------------------
class C
{
     public static void main(String[] args)
    {
       int a=10,b=0;
       try{
        System.out.println(a/b);
       }
       catch(Exception ex)
       {
           System.out.println(ex);
       }
        System.out.println("Test");
    }
 
}

user defined exceptions in java(throw)

-------------------------------------------------------

import java.util.*;
class UserDefinedException extends Exception
{

UserDefinedException(String msg)
{
super(msg);
}
public static void main(String args[])
{
Scanner S=new Scanner(System.in);

int x=133;
int y;
int result=0;
System.out.print("Enter the value of y: ");
try
{
y=S.nextInt();
if(y == 0)
{
UserDefinedException exp= new UserDefinedException("\nZero not allowed here");
throw exp;
}
if(y < 0)
{
UserDefinedException exp= new UserDefinedException("\nPlease Enter Positive Value");
throw exp;
}

System.out.println("\nYou entered: " + y);

result=x/y;
}

catch(UserDefinedException exp)
{

exp.printStackTrace();

}

catch(InputMismatchException obj)
{
System.out.println("\nEnter Number only.." +"\n"+obj);
}
     
System.out.println("\nResult of division: "+result);
}
}

Finally Keyword in Exception Handling

-------------------------------------------------
class C
{
     public static void main(String[] args)
    {
       int a=10,b=0;
       try{
        System.out.println(a/b);
       }
       catch(Exception ex)
       {
           System.out.println(ex);
       }
       finally
       {
            System.out.println("Test");
       }
     
    }
 
}