compare two objects in java [closed]

It's not clear where you're headed, but I'll try to respond with what I've understood so far:

If you can not have repeated elements, a Set (set) is the most appropriate data structure. It remains to know which set is best for you.

If your elements can be placed in a total order, then TreeSet is the most suitable: not only does it guarantee uniqueness but also keeps your elements in order:

Comparator<int[][]> c = new Comparator<int[][]>() {
    public int compare(int[][] a, int[][] b) {
        ...
    }
};
TreeSet<int[][]> c = new TreeSet<int[][]>(c);

Otherwise, a HashSet is more appropriate. However, comparing arrays in Java is done by reference, not by value. If you want content of the arrays to be compared, you must use a wrapper object that makes use of deepEquals deepHashCode :

class MeuObjeto {
    private int[][] array;

    public boolean equals(Object o) {
        if ( o instanceof MeuObjeto )
            return Arrays.deepEquals(this.array, ((MeuObjeto)o).array);
        else
            return false;
    }

    pubilc int hashCode() {
        return Arrays.deepHashCode(array);
    }
}
HashSet<MeuObjeto> c = new HashSet<MeuObjeto>();

Finally, if you want to use HashSet but would like the elements to be returned in the same order as they were entered, you can use LinkedHashSet instead. The example is identical to the previous item, it just changes the class.

Article for reference .