Using abstract classes and interfaces to sort arrays with algorithms

Question

Hi I'm just learning how to use abstract classes and interfaces. The code below is intended to be used by other classes to sort arrays in a number of different ways.

import java.util.Random;

public interface ArraySort {
// sorts the array using insertion sort

public default int[] sortInsertion(int[] array){
      int j;                     // the number of items sorted so far
      int key;                // the item to be inserted
      int i;  

      for (j = 1; j < array.length; j++)    // Start with 1 (not 0)
     {
            key = array[ j ];
            for(i = j - 1; (i >= 0) && (array[ i ] < key); i--)   // Smaller values are moving up
           {
                  array[ i+1 ] = array[ i ];
           }
          array[ i+1 ] = key;    // Put the key in its proper location
      }
    return array;
 }




// shuffles the array
public default int[] shuffle(int[] array){
    Random rgen = new Random();  // Random number generator         

    for (int i=0; i<array.length; i++) {
        int randomPosition = rgen.nextInt(array.length);
        int temp = array[i];
        array[i] = array[randomPosition];
        array[randomPosition] = temp;
    }

    return array;
}









// prints the array elements
public default void print(int[] array){
    System.out.println(array);
}











// initialize array from firstElement to lastElement
public int[] init(int firstElement, int lastElement);








}

I would like to know if this is necessarily an appropriate implementation of an abstract interface. Is there something that would make it much more efficient? Is there a better way to be doing this? What I want to know specifically is whether or not my code is 100% faithful to the concept of abstract classes and interfaces because I'm just trying to learn it in the best way possible.

Answer 1

Interfaces define methods without implementation. A class will then implement the interface and provide the method body.

Abstract classes cannot be instantiated, but they can be subclassed.

Here is a Java tutorial