Element.java

public class Element implements Comparable<Element>{
	String val;
	int count;
	String code = null;
	Element leftChild;
	Element rightChild;
	
	public Element(String v, int c){
		this.val = v;
		this.count = c;
		this.leftChild = null;
		this.rightChild = null;
	}
	
	public Element(Element l, Element r){
		this.leftChild = l;
		this.rightChild = r;
		this.count = l.getCount() + r.getCount();
		this.val = null;
	
	}
	
	public int getCount(){ return this.count; }
	
	public void propogate(String code){
		this.code = code;
		if(leftChild != null)
			leftChild.propogate(code+"0");
		if(rightChild != null)
			rightChild.propogate(code+"1");
	}
	
	@Override
	public int compareTo(Element e){
		if(this.getCount() > e.getCount())
			return 1;
		else if(this.getCount() == e.getCount())
			return 0;
		else
			return -1;
	}
	
	@Override
	public String toString(){
		return "Value = "+val+" Frequency = "+count+" Code = "+code;
	}
}

Main.java

import java.util.*;

public class Main {

	public static void main(String[] args) {
		int size = 7;
		Element[] list = new Element[size];
		ArrayList<Element> arr = new ArrayList<Element>();
		
		for(int i=0 ; i<size ; ++i){
			list[i] = new Element((i+1)+"", size-i);
			arr.add(list[i]);
		}
		
		while(arr.size() > 1){
			 Collections.sort(arr);
			 Element temp1 = arr.remove(0);
			 Element temp2 = arr.remove(0);
			 arr.add(new Element(temp1, temp2));
		}
		
		Element temp = arr.get(0);
		temp.propogate("");
		
		for(int i=0 ; i<list.length ; ++i){
			System.out.println(list[i]);
		}
		System.out.println("##.. End of Processing.. ");
	}

}

Output

Value = 1 Frequency = 7 Code = 10
Value = 2 Frequency = 6 Code = 00
Value = 3 Frequency = 5 Code = 111
Value = 4 Frequency = 4 Code = 110
Value = 5 Frequency = 3 Code = 010
Value = 6 Frequency = 2 Code = 0111
Value = 7 Frequency = 1 Code = 0110
##.. End of Processing.. 

Huffman Encoding...

sahii hai mahesh!!