inheritance in java

                                                                                                                     Inheritance Error Program 

                                                                                                             Inheritance Basic se Basic Program


                                                                                    

  












Program 3.p1
class Demo
{
     int boness= 1200;

}
class childDemo extends Demo{
     float bones= 3400;
   
    public static void main(String arg[])
    {
        childDemo s1= new childDemo();
        System.out.println(s1.bones);
        System.out.println(s1.bones);
    }
}

//Output
// C:\java>javac Testing.java

// C:\java>java childDemo
// 3400.0
// 3400.0




Program 4.p1

class Demo
{
     int boness= 1200;

}
class childDemo extends Demo{
     float bones= 3400;
   
    public static void main(String arg[])
    {
        childDemo s1= new childDemo();
        System.out.println(s1.bones);
        System.out.println(s1.boness);
    }
}

//Output
// C:\java>javac Testing.java

// C:\java>java childDemo
// 3400.0
// 1200



Program 5.p1

class Demo
{
     int boness;

}
class childDemo extends Demo{
     float bones;
   
    public static void main(String arg[])
    {
        childDemo s1= new childDemo();
        s1.boness=4324;
         s1.bones=2.30f;
        System.out.println(s1.boness);
       
        System.out.println(s1.bones);
    }
}

//Output
// C:\java>javac Testing.java

// C:\java>java childDemo
// 4324
// 2.3

// C:\java>

Program 6.p1
class Demo
{
     int boness;

}
class childDemo extends Demo{
     float bones;
   
    public static void main(String arg[])
    {
        childDemo s1= new childDemo();
       
        System.out.println(s1.boness);
        System.out.println(s1.bones);
        s1.boness=4324;
         s1.bones=2.30f;
    }
}

//Output
// C:\java>javac Testing.java

// C:\java>java childDemo
// 0
// 0.0




Program P1[7] This is compile time error
class Demo
{
     int boness;
 float bones;
}
class childDemo extends Demo{
   
   
    public static void main(String arg[])
    {  s1.boness=4324;
        s1.bones=2.30f;
        childDemo s1= new childDemo();
       
        System.out.println(s1.boness);
        System.out.println(s1.bones);
       
    }
}

//Output
// C:\java>javac Testing.java
// Testing.java:10: error: cannot find symbol
//     {  s1.boness=4324;
//        ^
//   symbol:   variable s1
//   location: class childDemo
// Testing.java:11: error: cannot find symbol
//          s1.bones=2.30f;
//          ^
//   symbol:   variable s1
//   location: class childDemo
// 2 errors

// C:\java>
// C:\java>




Program p1[8]
class Demo
{
     
}
class childDemo extends Demo{
    int boness;
 float bones;
   
    public static void main(String arg[])
    {  
        childDemo s1= new childDemo();
        s1.boness=4324;
        s1.bones=2.30f;
        System.out.println(s1.boness);
        System.out.println(s1.bones);
       
    }
}


Program p1[8]



Single inheritance 

Program p2[9]

class Demo
{
    void oldclass()
    {
System.out.println("This is parent class");
    }
     
}
class child extends Demo{
    void newclass()
    {
        System.out.println("This is a child class");
    }
   
    public static void main(String arg[])
    {  
        child s1= new child();
        s1.oldclass();
        s1.newclass();
        //System.out.println(s1.oldclass);
        //System.out.println(s1.newclass);
       
    }
}

//Output
// C:\java>javac Testing.java

// C:\java>java child
// This is parent class
// This is a child class

// C:\java>

Program p2[10]
class Demo
{
    void oldclass()
    {
System.out.println("parent class");
    }
     
}
class child extends Demo{
    void newclass()
    {
        System.out.println(" child class");
    }
   
    public static void main(String arg[])
    {  
        child s1= new child();
       
        System.out.println("This is"+s1.oldclass());
        System.out.println("This is a"+s1.newclass());
       
    }
}

//Output
C:\java>javac Testing.java Testing.java:19: error: 'void' type not allowed here System.out.println("This is"+s1.oldclass()); ^ Testing.java:20: error: 'void' type not allowed here System.out.println("This is a"+s1.newclass()); ^ 2 errors C:\java>


Program p3[11]
class Demo
{
    int a=30;
}
 class childDemo extends Demo
{
    int a=50;
}
class childDemo2 {
   
    public static void main(String[] args)
    {
       
        childDemo obj= new childDemo();
        System.out.println("Value of a:"+obj.a);
       
         Demo obj2 = new Demo();
        System.out.println("value of a :"+obj2.a);
   
    }
}

OutPut

C:\java>javac Testing.java

C:\java>java childDemo2
Value of a:50
value of a :30

C:\java>


Program P3[12]
class Demo
{
    int a=30;// This is instance Variable
}
 class childDemo extends Demo
{
//Declare an instance varibale whose name is same as that of the superclass instance
Varible name.

    int a=50;
}
class childDemo2 {
   
    public static void main(String[] args)
    {
       
        childDemo obj= new childDemo();
        System.out.println("Value of a:"+obj.a);
       
         Demo obj2(This is reference variable) = new Demo();
        System.out.println("value of a :"+obj2.a);
   
    }
}

Output
C:\java>javac Testing.java

C:\java>java childDemo2
Value of a:50
value of a :30

C:\java>

Program p3[13]
 class Demo
{
    int a=30;
}
 class childDemo extends Demo
{
    int a=50;
}
class childDemo2 {
   
    public static void main(String[] args)
    {
       
        childDemo obj= new childDemo();
        System.out.println("Value of a:"+obj.a);
       
         Demo obj2 = new Demo();
        System.out.println("value of a :"+obj2.a);
   
    }
}

// Output

// C:\java>javac Testing.java

// C:\java>java childDemo
// Error: Main method not found in class childDemo, please define the main method a
// s:
//    public static void main(String[] args)
// or a JavaFX application class must extend javafx.application.Application

// C:\java>

program p3[14]
 class Baseclass
{
  int x = 20;
 
// Overridden method.
   void msg()
   {
      System.out.println("Base class method");
   }
 }
 class Childclass extends Baseclass
{
  int x = 50;
  int y = 100;
// Overriding method.
   void msg()
   {
     System.out.println("Child class first method");
   }
void msg2()
{
   System.out.println("Child class second method");
 }
}
class MyTest extends Childclass {
public static void main(String[] args)
{
 Childclass obj = new Childclass();
 System.out.println("Value of x: " +obj.x); // x of class Childclass is called.
  obj.msg(); // msg() of Childclass is called.
  obj.msg2(); // msg2() of Childclass is called.
 
 Baseclass obj2 = new Childclass();
 System.out.println("Value of x: " +obj2.x); // x of Baseclass is called.

 //System.out.println("Value of y: " +obj2.y); // Error because y does not exist in Baseclass.
   obj2.msg(); // msg() of Childclass is called.
 //obj2.msg2(); // Error because the method msg2() does not exist in Baseclass.
  }
 }
    
Output                                                                                    
 C:\java>javac Testing.java

C:\java>java MyTest
Value of x: 50
Child class first method
Child class second method
Value of x: 20
Child class first method

C:\java>

program p3[15]
class Baseclass
{
  int x = 20;
  void msg()
    {
 System.out.println("Base class method");
  }
}
 class Childclass extends Baseclass
 {
  int x = 50;
  int y = 100;
  void msg()
 {
 System.out.println("Child class first method");
 }
 void msg2()
    {
 System.out.println("Child class second method");
 }
}
 class MyTest extends Childclass {
 public static void main(String args[]) {
     
 MyTest obj = new MyTest();
 obj.msg();
 
 
 }
 }

//  Output
//  C:\java>javac Testing.java

// C:\java>java MyTest
// Child class first method

// C:\java>


program p3[14]
class Baseclass
{
  int x = 20;
  void msg()
    {
 System.out.println("Base class method");
  }
}
 class Childclass extends Baseclass
 {
  int x = 50;
  int y = 100;
  void msg()
 {
 System.out.println("Child class first method");
 }
 void msg2()
    {
 System.out.println("Child class second method");
 }
}
 class MyTest extends Childclass {
 public static void main(String args[]) {
     
 MyTest obj = new MyTest();
 obj.msg();
 System.out.println("Value of x: " +obj.x);
  System.out.println("Value of x: " +obj.y);
  obj.msg2();
 }
 }
//  output
//  C:\java>javac Testing.java

// C:\java>java MyTest
// Child class first method
// Value of x: 50
// Value of x: 100
// Child class second method

// C:\java>

program p3[14]
 class Baseclass
{
  int x = 20;
  void msg()
    {
 System.out.println("Base class method");
  }
}
 class Childclass extends Baseclass
 {
  int x = 50;
  int y = 100;
  void msg()
 {
 System.out.println("Child class first method");
 }
 void msg2()
    {
 System.out.println("Child class second method");
 }
}
 class MyTest extends Baseclass {
 public static void main(String args[]) {
     
 MyTest obj = new MyTest();
 obj.msg();
 System.out.println("Value of x: " +obj.x);
 
 
 }
 }
 
Output
C:\java>javac Testing.java

C:\java>java MyTest
Base class method
Value of x: 20

C:\java>
 

program p3[14]
class Baseclass
{
  int x = 20;
  void msg()
    {
 System.out.println("Base class method");
  }
}
 class Childclass extends Baseclass
 {
  int x = 50;
  int y = 100;
  void msg()
 {
 System.out.println("Child class first method");
 }
 void msg2()
    {
 System.out.println("Child class second method");
 }
}
 class MyTest extends Baseclass {
 public static void main(String args[]) {
     
 
 
  Baseclass obj2 = new Childclass();
  obj2.msg();
  System.out.println("Value of x: " +obj2.x);
   
 
 }
 }
 C:\java>javac Testing.java

C:\java>java MyTest
Child class first method
Value of x: 20

C:\java>

program p3[14]
program p3[14]
program p3[14]
program p3[14]
program p3[14]program p3[14]
















Multilevel inheritance


class Demo
{
   
    void oldclass()
    {
System.out.println("parent class");
    }
     
}
class childd extends Demo{
    void newclass()
    {
       
        System.out.println(" child class");
    }
}
class secnewclass extends childd{

    void secnewclass(){
        System.out.println("secend child class");
    }


    public static void main(String arg[])
    {  
        secnewclass s1= new secnewclass();
        s1.oldclass();
        s1.newclass();
        s1.secnewclass();
       
       
    }
}
    //Output
   
// C:\java>javac Testing.java

// C:\java>java secnewclass
// parent class
//  child class
// secend child class

// C:\java>


Hierarchical Inheritance 















































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