The length of an array is the number of elements of the array. The dimensions of an array type of int[][][] is three. 
    Object o = new int[1][2][3];
    
    // Get length
    int len = Array.getLength(o);  // 1
    
    // Get dimension
    int dim = getDim(o);           // 3
    
    // If `array' is an array object returns its dimensions; otherwise returns 0
    public static int getDim(Object array) {
        int dim = 0;
        Class cls = array.getClass();
        while (cls.isArray()) {
            dim++;
            cls = cls.getComponentType();
        }
        return dim;
    }