Simple way to compare 2 ArrayLists

This should check if two lists are equal, it does some basic checks first (i.e. nulls and lengths), then sorts and uses the collections.equals method to check if they are equal.

public  boolean equalLists(List<String> a, List<String> b){     
    // Check for sizes and nulls

    if (a == null && b == null) return true;


    if ((a == null && b!= null) || (a != null && b== null) || (a.size() != b.size()))
    {
        return false;
    }

    // Sort and compare the two lists          
    Collections.sort(a);
    Collections.sort(b);      
    return a.equals(b);
}

Convert Lists to Collection and use removeAll

    Collection<String> listOne = new ArrayList(Arrays.asList("a","b", "c", "d", "e", "f", "g"));
    Collection<String> listTwo = new ArrayList(Arrays.asList("a","b",  "d", "e", "f", "gg", "h"));


    List<String> sourceList = new ArrayList<String>(listOne);
    List<String> destinationList = new ArrayList<String>(listTwo);


    sourceList.removeAll( listTwo );
    destinationList.removeAll( listOne );



    System.out.println( sourceList );
    System.out.println( destinationList );

Output:

[c, g]
[gg, h]

[EDIT]

other way (more clear)

  Collection<String> list = new ArrayList(Arrays.asList("a","b", "c", "d", "e", "f", "g"));

    List<String> sourceList = new ArrayList<String>(list);
    List<String> destinationList = new ArrayList<String>(list);

    list.add("boo");
    list.remove("b");

    sourceList.removeAll( list );
    list.removeAll( destinationList );


    System.out.println( sourceList );
    System.out.println( list );

Output:

[b]
[boo]

Convert the List in to String and check whether the Strings are same or not

import java.util.ArrayList;
import java.util.List;



/**
 * @author Rakesh KR
 *
 */
public class ListCompare {

    public static boolean compareList(List ls1,List ls2){
        return ls1.toString().contentEquals(ls2.toString())?true:false;
    }
    public static void main(String[] args) {

        ArrayList<String> one  = new ArrayList<String>();
        ArrayList<String> two  = new ArrayList<String>();

        one.add("one");
        one.add("two");
        one.add("six");

        two.add("one");
        two.add("two");
        two.add("six");

        System.out.println("Output1 :: "+compareList(one,two));

        two.add("ten");

        System.out.println("Output2 :: "+compareList(one,two));
    }
}