ArrayListExample

// Find out why it throws exception at  list.remove(d);

import java.util.ArrayList;
import java.util.Iterator;

public class ArrayListExample {

        @SuppressWarnings("rawtypes")
        public static void main(String[] args) {
     
        ArrayList<Comparable> list=new ArrayList<Comparable>();   
        //ArrayList<Integer> list=new ArrayList<Integer>();
        int a=8;
        String b="Anand";
        boolean c=true;
        list.add(a);
        list.add(b);
        list.add(c);
        int size=list.size();
            System.out.println("The size of list is :  "+size);
            int indexc=list.indexOf(c);
            System.out.println("The Index of c is :  "+indexc);
            char d='A';
            list.add(2, d);
            System.out.println("The size of list is :  "+size);
            indexc=list.indexOf(c);
            System.out.println("The Index of c is :  "+indexc);
            System.out.println("The value of d is :  "+list.get(list.indexOf(d)));
            list.remove(d);
            //System.out.println("The Index of c is :  "+list.get(list.indexOf(d)));
        Iterator<Comparable> itr=list.iterator();
        while(itr.hasNext())
        {
            System.out.println("The elements of list are:   "+itr.next());
        }
        }
}

Static Variable Example

public class StaticExample {

    public static void main(String [] args)
    {
        StaticMethod sm =new StaticMethod();
        StaticMethod sm1 =new StaticMethod();
        sm.getValue(25,25);
        sm1.getValue(30,30);
        int val1=sm.var1;
        int val2=sm1.var1;
        int val3=sm.var2;
        int val4=sm1.var2;
        System.out.println("The value of 1st static instance:  "+val1+"" +
                "   The value of 2nd static instance:  "+val2);
       
        System.out.println("The value of 1st non static instance:  "+val3+"" +
                "   The value of 2nd non static instance:  "+val4);
    }
}

class StaticMethod {
   
    static int var1;
    int var2;
   
    public void getValue(int val1, int val2)
    {
        var1=val1;
        var2=val2;
       
        //return a;
    }

   
}

PrimeNumbers with Scanner

import java.util.*;

class PrimeNumbers
{
   public static void main(String args[])
   {
      int n, status = 1, num = 3;

      Scanner in = new Scanner(System.in);
      System.out.println("Enter the number of prime numbers you want ");
      n = in.nextInt();

      if ( n >= 1 )
      {
         System.out.println("First "+n+" prime numbers are :-");
         System.out.println(2);
      }

      for ( int count = 2 ; count <=n ;  )
      {
         for ( int j = 2 ; j <= Math.sqrt(num) ; j++ )
         {
            if ( num%j == 0 )
            {
               status = 0;
               break;
            }
         }
         if ( status != 0 )
         {
            System.out.println(num);
            count++;
         }
         status = 1;
         num++;
      }        
   }
}

Print output without semicolon

interface abc
{
int a=10;   
}
public class SemiColon implements abc{
   
    public static void main(String [] args ){
        if (System.out.printf("Hello World", null).toString().length() > 20){ }       
//Example of ternary operator  
    int a=2;
    int b=3;
    int c=4;
    System.out.println((a>b?a:b)>c?(a>b?a:b):c);
    }
}

OverrideStatic

//Static method cannot be overridden. Look into the following code:
class ParentClass {
    public void method1(){
        System.out.println("Parent Method1");
    }
    public static void method2(){
        System.out.println("Parent Method2");
    }
}



class ChildClass extends ParentClass{
    public void method1(){
        System.out.println("Child Method1");
    }
    public static void method2(){
        System.out.println("Child Method2");
    }
}

public class OverrideStatic {
    public static void main(String args[]){
        ParentClass parent;
        ChildClass child = new ChildClass();
        parent = child;
        parent.method1();
        parent.method2();
    }
}

Why-is-the-tostring-method-being-called-when-i-print-an-object

//Example why-is-the-tostring-method-being-called-when-i-print-an-object
//Because PrintStream.println has an overload that takes an Object, and then calls //itstoString method
public class ABC {
    public static void main(String[] args) {
        Coin1 q = new Quarter1();
        System.out.println("I am calling get value on coin " + q.getABC());
   
        System.out.println(q);
     
    }
}

  class Money1 {
    private int value;

    public Money1(int v) {
        value=v;
    }

    public  int getValue()
    {
    return value;
    }

    protected int myValue() {
        return value;
    }

    public  String toString()
    {
    return "Anand";
  }
}

  class Coin1 extends Money1 {
    public Coin1(int value) {
        super(value);
        System.out.println("I am a coin, my value is " + getValue());
    }
 
    public int getABC() {
        return 23;
    }

}

 class Quarter1 extends Coin1 {
    public Quarter1 () {
        super(25);
    }

    public int getValue() {
        return myValue();
    }

    public String toString() {
        return "A Quarter is "+getValue();
    }
}

Constructor Calling

public class Test {

public static void main(String args[])
{
//Constructor related code block
System.out.println(args.length);
Parent a=new Parent();
System.out.println("1");
Child b=new Child();
System.out.println("2");
Parent c=new Child();
System.out.println("3");
//Child d=(Child)new Parent();
Parent d=(Parent) new Child();
System.out.println("4");
a.Method(34);
System.out.println("5");
b.Method(56);
System.out.println("6");
c.Method(102);
System.out.println("7");
d.Method(123);
}
}

public class Parent {

public Parent()
{
this("Anand");
System.out.println("Parent Constructor");
}

public Parent(String args)
{
System.out.println("Parent Constructor with args");
}

public void Method(int args)
{
System.out.println("Parent");
System.out.println(args);
}

}

public class Child extends Parent{

public Child()

{

this("Anand");

//super();

//this.thisCall();

//Child("Annad");

System.out.println("Child Constructor");

}

public Child(String args)

{

System.out.println("Child Constructor calling with args cons");

}

public void thisCall()

{

System.out.println("Child Constructor calling this");

}

public void Method(int args)

{

System.out.println("Child");

System.out.println(args);

}

}

SerializationDemo

import java.io.*;
public class SerilizationExm {

public static void main(String args[])
{
int i=10;
int j=0;
long start = System.currentTimeMillis ();
//Serializing object

MyClass2 a= new MyClass2();
try {
MyClass1 object1=new MyClass1("Anand",27,1984,a);
System.out.println("Object1:     "+object1);
FileOutputStream fos=new FileOutputStream("Stream");
ObjectOutputStream oos=new ObjectOutputStream(fos);
oos.writeObject(object1);
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

try {
MyClass1 object2;
//System.exit (0);
//Runtime.getRuntime().exit(0);
FileInputStream fis=new FileInputStream("Stream1");
ObjectInputStream ois=new ObjectInputStream(fis);
object2=(MyClass1)ois.readObject();
System.out.println("Object2:     "+object2);
//System.exit (0);
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
//e.printStackTrace();
System.out.println("File name mentioned does not exists");
}
catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
finally
{
try
{
System.out.println("This is finally Method"+i/j);
}
catch(ArithmeticException e)
{
System.out.println("Exception in finally");
//e.printStackTrace();
}
}
long end = System.currentTimeMillis ();

System.out.println ("Time taken for execution is " + (end - start)+"  In milli seconds");
}
}

 class MyClass1 implements Serializable
 {
String s;
static  int c=2;
String d;
int a;
long b;
public MyClass1(String ab,int bc,long ac,MyClass2 abc )
{
s=ab;
a=bc;
b=ac;
d=abc.aMethod();
}

public String toString()
{
//d=(new MyClass2()).aMethod();
return "s="+s+";a="+a+";b="+b+";c="+c+";d="+d;
}


 }

 class MyClass2
 {
public String aMethod()
{
return "Prakash";
}
 }

ArrayinArray

public class ArraySort {

    public static void main(String []args)
    {
        int length = 9999;
        int search[]={0,0,0,0};
        int pattern[]= {1,3,2,4};
        int data[]= {62,58,3,15,6,5,60,1,7,8,22,3,9,4,1,2,9,7,35,4,2,8,80,6,5,3,73,6,1};
        for ( int i=0; i<data.length; i++ )
        {
            if ( data[i] == pattern[0] || data[i] == pattern[1] || data[i] == pattern[2] || data[i] == pattern[3] )
            {
                for(int k=0; k<4; k++)
                {      
                    search[k]=0;
                }
                for(int j=i; j<data.length; j++)
                {
                    if     ( data[j] == pattern[0] )
                        search[0]=1;
                    if ( data[j] == pattern[1] )
                        search[1]=1;
                    if ( data[j] == pattern[2] )
                        search[2]=1;
                    if ( data[j] == pattern[3] )
                        search[3]=1; 
                    if (search[0] == 1 && search[1] == 1 && search[2] == 1 && search[3] == 1)          
                    {
                        if (length > j-i+1)
                        {
                            length=j-i+1;
                            break;
                        }
                    }
                }             
            } 
        }
        System.out.println ("The Smallest length for the pattern is :"+length);

    }
}