collection

ArrayList.java

package collection;
import java.util.*;
public class Arraylistdemo {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		ArrayList arr =new ArrayList();
		arr.add("vivek");
		arr.add("sumit");
		arr.add("vikash");
		Integer n=new Integer(5);
		arr.add(n);
		arr.add("vivek");
		//System.out.println(arr);
		/*Iterator itr=arr.iterator();
		while(itr.hasNext())
		{
			System.out.println(itr.next());
		}
		*/
	ListIterator itr=arr.listIterator();
	while(itr.hasNext())
	{  itr.next();
	
	}
	while(itr.hasPrevious())
	{
	 System.out.println(itr.previous());
	}
	}

}

MapKeyDemo.java

package collection;

public class Mapkey {
	String name;
	String post;
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getPost() {
		return post;
	}
	public void setPost(String post) {
		this.post = post;
	}	

}

MapsetDemo.java

package collection;
import java.io.ObjectOutputStream.PutField;
import java.util.*;
public class mapsetDemo {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
    // HashMap hp=new HashMap();/*either and thither*/
		//LinkedHashMap hp=new LinkedHashMap();/*as usualr*/
		TreeMap hp= new TreeMap();/*asscending order*/
     hp.put("tv",new Double(150000));
     hp.put("aefrigator",new Double(1500000));
     hp.put("destop",new Double(150000));
     hp.put("laptop",new Double(1000));
     hp.put("tab",new Double(17500));
     hp.put("tv",new Double(145000));
     Set set=hp.entrySet();
     Iterator itr=set.iterator();
     while(itr.hasNext())
     {
    	   Map.Entry obj =(Map.Entry)itr.next();
    	   System.out.println(obj.getKey()+"=====>"+obj.getValue());
     }
     
     
	}

}

MapSetTwoKeyvalue.java

package collection;
import java.util.*;

import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;

public class Mapsetonekeytwovalue {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		TwokeyforMapset x1 = new TwokeyforMapset();
		TwokeyforMapset x2 = new TwokeyforMapset();
		TwokeyforMapset x3 = new TwokeyforMapset();
		x1.setRl("1");
		x1.setSr("D1");
		x2.setRl("2");
		x2.setSr("D2");
		x3.setRl("3");
		x3.setSr("D3");
      Mapkey m1=new Mapkey();
      Mapkey m2=new Mapkey();
      Mapkey m3=new Mapkey();
      m1.setName("kolkata");
      m1.setPost("hr");
      m2.setName("chennai");
      m2.setPost("Finance");
      m3.setName("Mumbai");
      m3.setPost("Mktu");
       HashMap hp= new HashMap();
        hp.put(x1,m1);
        hp.put(x2,m2);
        hp.put(x3,m3);
        Set set=hp.entrySet();
        Iterator itr=set.iterator();
        while(itr.hasNext())
        {
       	   Map.Entry obj =(Map.Entry)itr.next();
        	Mapkey tp=(Mapkey)obj.getValue();
        	TwokeyforMapset pt =(TwokeyforMapset)obj.getKey();
       	   System.out.println(pt.getSr()+"====>"+pt.getRl()+"=====>"+tp.getName()+"====>"+tp.getPost());
        }
       
      
	}

}

SetDemo.java

package collection;
import java.util.*;
public class setdemo {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
    //HashSet h =new HashSet();
   // LinkedHashSet h =new LinkedHashSet();
		TreeSet h =new TreeSet();
    h.add("vivek");
    h.add("akash");
    h.add("suraj");
    h.add("rohan");
    h.add("hello");
    h.add("anish");
    h.add("vivek");
    Iterator itr=h.iterator();
    //System.out.println(h);
    while(itr.hasNext())
    {
    	System.out.println(itr.next());
    }
  }
}

TwokeyforMapset.java

package collection;

public class TwokeyforMapset {
	String sr;
	String rl;
	public String getSr() {
		return sr;
	}
	public void setSr(String sr) {
		this.sr = sr;
	}
	public String getRl() {
		return rl;
	}
	public void setRl(String rl) {
		this.rl = rl;
	}
	

}

UserdefinedArraylist.java

package collection;
import java.util.*;
class Product
{ String pname;
  double price;
  
  public Product(String pname,double price)
  {
	  this.pname=pname;
	  this.price=price;
	  
	  
  }
  public String toString()
  {
	  return(pname+"----->"+price);
	  
  }

}

public class UserdefinedArrayList {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
      ArrayList arr = new ArrayList();
      arr.add(new Product("Tv",15000));
      arr.add(new Product("har",10000));
      Iterator itr=arr.iterator();
      while(itr.hasNext())
    	  
      {System.out.println(itr.next());
      
	}
	}
}

UserdefinedArraylistusingPOJO.java

package collection;

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

public class UserdefinedArrayListusingPOJO {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Product_master p1=new Product_master();
		Product_master p2=new Product_master();
		Product_master p3=new Product_master();
		Product_master p4=new Product_master();
		p1.setPname("tv");
		p1.setPrice(10000.00);
		p2.setPname("Refrigator");
		p2.setPrice(20000.00);
		p3.setPname("Tabv");
		p3.setPrice(90000.00);
		p4.setPname("laptop");
		p4.setPrice(30000.00);
		ArrayList arr=new ArrayList();
		arr.add(p1);
		arr.add(p2);
		arr.add(p3);
		arr.add(p4);
		Iterator itr=arr.iterator();
		while(itr.hasNext()){
			  Product_master pm=(Product_master)itr.next();
			  System.out.println(pm.getPname()+"====>"+pm.getPrice());
			  			             
		}
	}
}
//Pojo class Product_master for UserdefinedArraylistusingPOJO.java
/*
	package collection;

public class Product_master {
	String pname;
	double price;
	
	public String getPname() {
		return pname;
	}
	public void setPname(String pname) {
		this.pname = pname;
	}
	public double getPrice() {
		return price;
	}
	public void setPrice(double price) {
		this.price = price;
	}
}  
 
*/

Some basic important code of Collection Class in java.