Java Functions

class intWrap {
   int x;
} 
public class Main { 
    public static void main(String[] args) {
       intWrap i = new intWrap();
       i.x = 10;
       intWrap j = new intWrap();
       j.x = 20;
       swap(i, j);
       System.out.println("i.x = " + i.x + ", j.x = " + j.x);
    } 
    public static void swap(intWrap i, intWrap j) {
       int temp = i.x;
       i.x = j.x;
       j.x = temp;
    }
}

class Main {
    public static void main(String args[]) {   
             System.out.println(fun());
    }   
    static int fun(int x = 0)
    {
      return x;
    }
}

class Test
{
    public static void main(String[] args)
    {
        StringBuffer a = new StringBuffer("geeks");
        StringBuffer b = new StringBuffer("forgeeks");
        a.delete(1,3);
        a.append(b);
        System.out.println(a);
    }
}

 class Test
{

    public static void main(String[] args)
    {
        String obj1 = new String("geeks");
        String obj2 = new String("geeks");

        if(obj1.hashCode() == obj2.hashCode())
            System.out.println("hashCode of object1 is equal to object2");

        if(obj1 == obj2)
            System.out.println("memory address of object1 is same as object2");

        if(obj1.equals(obj2))
            System.out.println("value of object1 is equal to object2");
    }
}

 class Test implements Cloneable
{
    int a;

    Test cloning()
    {
        try
        {
            return (Test) super.clone();
        }
        catch(CloneNotSupportedException e)
        {
            System.out.println("CloneNotSupportedException is caught");
            return this;
        }
    }
}

class demo
{

    public static void main(String args[])
    {
        Test obj1 = new Test();
        Test obj2;
        obj1.a = 10;
        obj2 = obj1.cloning();
        obj2.a = 20;

        System.out.println("obj1.a = " + obj1.a);
        System.out.println("obj2.a = " + obj2.a);
    }
}

class Test
{
    public static void main(String[] args)
    {
        String str = "geeks";
        str.toUpperCase();
        str += "forgeeks";
        String string = str.substring(2,13);
        string = string + str.charAt(4);;
        System.out.println(string);
    }
}