核心：冒泡，持续比较相邻元素，大的挪到后面，因此大的会逐步往后挪，故称之为冒泡。
实现
Python

#!/usr/bin/env python
def bubbleSort(alist):
    for i in xrange(len(alist)):
        print(alist)
        for j in xrange(1, len(alist) - i):
            if alist[j - 1] > alist[j]:
                alist[j - 1], alist[j] = alist[j], alist[j - 1]
    return alist
unsorted_list = [6, 5, 3, 1, 8, 7, 2, 4]
print(bubbleSort(unsorted_list))

Java

public class Sort {
    public static void main(String[] args) {
        int unsortedArray[] = new int[]{6, 5, 3, 1, 8, 7, 2, 4};
        bubbleSort(unsortedArray);
        System.out.println("After sort: ");
        for (int item : unsortedArray) {
            System.out.print(item + " ");
        }
    }
    public static void bubbleSort(int[] array) {
        int len = array.length;
        for (int i = 0; i < len; i++) {
            for (int item : array) {
                System.out.print(item + " ");
            }
            System.out.println();
            for (int j = 1; j < len - i; j++) {
                if (array[j - 1] > array[j]) {
                    int temp = array[j - 1];
                    array[j - 1] = array[j];
                    array[j] = temp;
                }
            }
        }
    }
}

复杂度分析
平均情况与最坏情况均为 O(n2)O(n^2)O(n2), 使用了 temp 作为临时交换变量，空间复杂度为 O(1)O(1)O(1).