PrintDuplicates.java

package coding;

import java.util.Arrays;
import java.util.HashMap;
import java.util.LinkedHashSet;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;

import org.testng.annotations.Test;

public class PrintDuplicates extends BaseTestNg {

	int[] data= {1,3,8,3,11,5,6,4,7,6,7};

	@Test(priority=1)
	public void usingArraysSort() {
		Arrays.sort(data);
		for (int i = 0; i < data.length -1 ; i++) {
			if(data[i] == data[i+1]){
				System.out.println(data[i]);
			}
		}
	}
	
	@Test(priority=2)
	public void usingSet() {
		int n=data.length;
		Set<Integer> dupNumbers = new LinkedHashSet<Integer>();
		for(int i=0;i<n;i++) {
			if(!dupNumbers.add(data[i])) {
				System.out.println(data[i]);
			}
		}
	}

	@Test(priority=3)
	public void usingForLoop() {
		Map<Integer,Integer> allDups = new HashMap<Integer,Integer>();
		for (int i = 0; i < data.length -1 ; i++) {
			if(allDups.containsKey(data[i])) 
				allDups.put(data[i], allDups.get(data[i])+1);
			else
				allDups.put(data[i], 1);
		}
		
		for (Entry<Integer, Integer> eachEntry : allDups.entrySet()) {
			if(eachEntry.getValue() > 1) {
				System.out.println(eachEntry.getKey());
			}
		}
		
	}

}