Bubble Sort Algorithm using Java

In Bubble Sort, smaller elements bubbles to top of list in ascending sorting hence it's called Bubble Sort.

How it works :

1. In Bubble Sort, You take first element and second element initially and compare both elements.
2. If second element is smaller than first element then you swipe places. how? using temp :) as below
3. You keep doing same meaning stepping through array and comparing element with pair of adjacent elements until no swapping required and you have sorted array

Java Program using Bubble Sort Algorithm :

package com.anuj.algorithms;

public class BubbleSort {

    protected void doBubbleSort(int data[], String sortingType) {
        int temp;
        for (int i = 0; i < data.length; i++) {

         //data[i] - individual array values
            for (int j = 0; j < data.length - 1; j++) {
                if (sortingType.equalsIgnoreCase("Ascending")) {
                    if (data[j] > data[j + 1]) {
                        temp = data[j];
                        data[j] = data[j + 1];
                        data[j+1] = temp;
                    }
                } else if (sortingType.equalsIgnoreCase("Descending")) {
                    if (data[j] < data[j + 1]) {
                        temp = data[j];
                        data[j] = data[j + 1];
                        data[j+1] = temp;
                    }
                }
            }
        }
        System.out.println("\nArray After " + sortingType + " Sorting : ");
        printArray(data);
    }

    protected void printArray(int[] data) {
        for (int i = 0; i < data.length; i++) {
            System.out.print(data[i]);
            if(i < data.length-1) {
             System.out.print(" "); 
            }
        }
    }

    public static void main(String[] args) {
        BubbleSort bubbleSort = new BubbleSort();

        int data[] = {1, 2, 33, 56, 8, 31};
        System.out.println("Array Before Sorting : ");
        bubbleSort.printArray(data);
        
        bubbleSort.doBubbleSort(data, "Ascending");        
        bubbleSort.doBubbleSort(data, "Descending");
    }
}

Output :

Array Before Sorting : 
1 2 33 56 8 31
Array After Ascending Sorting : 
1 2 8 31 33 56
Array After Descending Sorting : 
56 33 31 8 2 1