what is enumeration in java

1public class DaysOfTheWeek {
2
3    public enum Days {m, t, w, r, f, sat, s};
4  	    public static void main(String[] args) {
5          Days d = Days.t; 
6          System.out.println(d);
7          //the output would be t
8        }
9}

1public enum Feu {
2
3    VERT(0), ORANGE(1), ROUGE(2);
4
5
6    private int value;
7
8    private Feu( int value ) {
9        this.value = value;
10    }
11
12    public int toInt() {
13        return value;   
14    }
15    
16    public static Feu fromInt( int value ) {
17        switch( value ) {
18            case 0: return VERT;
19            case 1: return ORANGE;
20            default: return ROUGE;
21        }
22    }
23    
24}
25