As a Computer Science Student, when we start learning about DSA, we will find the Sorting Algorithm concept. In that concept, we must implement different Sorting Methods with a programming language. One such programming problem is “Bubble Sort in Java”.
There are very few Real-world Applications of the Bubble Sort Algorithm. However, it can still be used for Teaching and Learning purposes. In this article, we will first define the definition of Bubble Sort Algorithm.
Later, we will check its detailed implementation process with a Flowchart or Diagram. We will also use a Java program to implement it practically. So, let us start our discussion.
TL;DR: Bubble Sort In Java
Aspect | Summary |
Core Concept | Bubble Sort compares adjacent elements and swaps them using an “imaginary bubble” until the array is sorted. No recursion or sub-array splitting is required. |
Implementation Logic |
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Complexities | Best Case time complexity is O(n), Average and Worst Cases are O(n²). Space Complexity is O(1) for in-place element swapping. |
Advanced Variations | Cocktail Shaker Sort, Odd-Even Sort, and Recursive Bubble Sort. |
Pros And Cons |
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What Is Bubble Sort Algorithm? Read Below
Bubble Sort is a Comparison-Based Algorithm where two elements are being compared in any Array. If the two elements are in the wrong order, then there should be an Element Swapping. And this complete process will be done throughout the array to sort the Elements in a proper order.
When we are comparing the elements, we will create an Imaginary Bubble around them. The element swapping will be done inside of that bubble. Once the Element is swapped, the Bubble will be shifted towards the next to do the same job again on two different elements.
For solving different problems, there are different types of sorting algorithms. Like, there are Merge Sort Algorithms, Quick Sort Algorithm, Heap Sort Algorithm & many others. Developers use their sense of algorithm while picking up one specific sorting algorithm for question-solving purposes.
Historical Evolution Of Bubble Sort Algorithm: [H4]
- 1950s: The Bubble Sort was introduced as one of the first sorting techniques.
- 1960s: The Bubble Sort was Officially Documented in Books and used in Programming Courses.
- 1970s: At this time, it was first identified that the Bubble Sort is slower than the Quick and Merge Sort.
- 1980s: We can see a decline in Bubble Sort practical usage as it was marked as Slower.
- 1990s: Bubble Sort Algorithm was tried to optimize for increasing the performance.
- 2000s: The Bubble Sort Algorithm remains a tool for teaching sorting concepts.
Understanding Bubble Sort Algorithm With Flowchart:
Now, it is time to understand the Bubble Sort Algorithm Theory with a Flowchart. We will describe the flowchart in a step-by-step format.
Let us assume that there is a Random Array with elements 2, 1, 4, and 3. And we want to sort it in Ascending Order using the Bubble Sort. In that case, we will start with the Step 1.
Step 1: First Bubble
In the beginning, a Bubble will be created on the Element 2 and the Element 1. As they are not placed in Ascending Order, the elements will be swapped. And Element 1 will be the First and Element 2 will be the Second.
Step 2: Second Bubble
Now, the Second Bubble will be created on the Next Element Pair. The Next Pair will be Element 2 and Element 4. We can see the Element Pair is in the Right Order, i.e. Ascending Order. So, there will be no Element Swapping and Bubble will move to the next.
Step 3: Third Bubble
The third bubble will be created on the Element 4 and the Element 3. In this case, both elements are not in Ascending Order. So, the Element Swapping will be done. Element 3 will be the Third, and Element 4 will be the Last Element of the array.
Hence, the array is now in complete Ascending Order. So, the Bubble Sort Algorithm will end here.
What Is The Algorithm Of The Java Bubble Sort?
Now, before we move toward the detailed implementation of the Bubble Sort, we should clear the process by discussing the Algorithm of the Bubble Sort Method.
Let us check the following Algorithm Points that will help to develop the Programming Logic later.
- The Code will start with the Integer Array.
- A Loop will Iterate from 0 to the N-1. N is the size of the Array.
- Now, an Inner Loop will iterate from 0 to N-I-2. The I is the Index of the Outer Loop.
- Inside of the loops, a Condition will develop like A[j] > A[j + 1]. It will check whether the Previous Element is larger than the Next Element.
- If that is True, then the Swapping of elements will be done.
How To Implement Bubble Sort Algorithm With Java?
The bubble Sort algorithm in Java programming language is developed upon the concept of the function call & nested loop.
So, before moving to the Implementation of the Bubble Sort Algorithm in Java, you should have the Basic Knowledge of Function Calls and Nested Loops. Otherwise, you will find the implemented program a bit difficult to understand.
public class Main{
static void bubble(int[] a) // Implementation Of Bubble Sorting Algorithm
{
int x = a.length; // Getting The Size Of The Array
int t = 0; // Local Variable Declaration
for(int i=0; i < x; i++) // Outer For Loop Implementation
{
for(int j=1; j < (x-i); j++) // Inner For Loop Implementation
{
if(a[j-1] > a[j]) // Checking The Condition To Get Higher Value
{
// Swapping The Elements
t = a[j-1];
a[j-1] = a[j];
a[j] = t;
}
}
}
}
public static void main(String[] args) {
int b[] ={2,4,3,8}; // Assigning The Array Value
System.out.println("Before Implementation Of Bubble Sort: "); // Printing Random Statement
for(int i=0; i < b.length; i++) // For Loop For Printing The Previous Value
{
System.out.print(b[i] + " "); // Printing Each & Every Elements
}
System.out.println(); // Next Line Implementation
bubble(b); // Calling The User-Defined Function From Main Function
System.out.println("After Implementation Of Bubble Sort: "); // Printing Random Statement
for(int i=0; i < b.length; i++) // For Loop For Printing The New Value
{
System.out.print(b[i] + " "); // Printing Each & Every Elements
}
}
}
Steps Of The Program:
- At first, we will declare the array of integers. Those integers’ values will be placed in an unsorted manner.
- In the program, we first printed the elements of the array before moving to the sorting.
- After printing the elements, the function will be called for doing the Bubble Sort.
- Inside the function, nested for loops will be implemented. Inside the nested for loop, the condition to check the elements will be declared.
- If the conditions are true, then the swapping of the elements will be done inside of the for loop.
- In this way, the complete process will be executed. For the swapping purpose, one local variable has also been declared inside of that function.
- After all these operations are completed, we are good to go for the printing of the elements in the array.
- Now, the elements in the array are in a sorted manner. The complete Bubble Sort algorithm in Java programming language is done.
Output:
How To Implement Bubble Sort Java For String Arrays?
The Bubble Sort Algorithm is not only applicable to numbers. With the Java Bubble Sort, we can even sort the String Arrays. But, in that case, the comparison of the strings will not be the same as we did for numbers.
Let us check the following code, where the complete implementation of Bubble Sort for strings has been done.
public class Main
{
static void BubbleStrings(String[] zap)
{
int z = zap.length; // Getting The Length Of String
for (int i = 0; i < z - 1; i++)
{
for (int j = 0; j < z - i - 1; j++)
{
// Using compareTo() To Compare Two Strings
if (zap[j].compareTo(zap[j + 1]) > 0)
{
// The Strings Will Be Swapped
String tmp = zap[j];
zap[j] = zap[j + 1];
zap[j + 1] = tmp;
}
}
}
}
public static void main(String[] args)
{
String[] data = {"Coding", "Zap", "One", "Java"}; // String Values
System.out.println("String Before Bubble Sort:");
for (String s : data)
System.out.print(s + " ");
BubbleStrings(data); // Calling The Function
System.out.println("\nString After Bubble Sort:");
for (String s : data)
System.out.print(s + " ");
}
}
Steps Of The Program:
- At first, an array of string values will be taken, and the BubbleStrings() function will be called.
- In the function, we will first get the array length and execute two nested loops.
- In those nested loops, the string comparison will be done using the CompareTo() function.
- Then, the strings will be swapped based on their alphabetical order.
- By such swapping, the entire end string array will be formed, and we will print it.
Output:
What Is The Time And Space Complexity Of The Bubble Sort Algorithm?
Now, it is time to discuss the Time Complexity and Space Complexity. On the Time Complexity and Space Complexity, the efficiency of any Sorting Algorithm depends.
So, let us first check the Time Complexity from the following list.
- If the Elements in the Array are already sorted, then it will be the Best Case. For that case, the Time Complexity will be O(n).
- If the Elements in the Array are in Random Order, then it will be the Average Case where the Time Complexity is O(n ^2).
- If the Elements in the Array are in Reverse Order, then it will be the worst case where the Time Complexity will be O(n ^2).
The Space Complexity is Constant in the Bubble Sort Algorithm, which doesn’t rely on the Array Size. The Space Complexity of the Bubble Sort Algorithm will be O(1).
“Understanding why O(n²) is considered ‘slow’ compared to O(n log n) is vital for exams; you can book a DSA tutoring session to master complexity analysis.”
How To Optimize Java Bubble Sort With Swap Flag?
As per the implementation theory of Bubble Sort, an array has to pass multiple iterations even after the array has already become sorted. This makes the bubble sort iterations slower. But you can easily optimize it.
To optimize the Java Bubble Sort, you have to use a Boolean Swap Flag that will terminate the iteration whenever the array becomes sorted. Let us check the following code for its implementation.
public class Main
{
static void Optimized(int[] zap)
{
int z = zap.length; // Getting The Array Length
boolean flag; // The Swapping Flag
for (int i = 0; i < z - 1; i++)
{
flag = false; // The Flag Will Be Set To False
// Comparing The Adjacent Elements
for (int j = 0; j < z - i - 1; j++)
{
if (zap[j] > zap[j + 1])
{
// Swapping Of The Elements
int tmp = zap[j];
zap[j] = zap[j + 1];
zap[j + 1] = tmp;
// Flag Becomes True After Swapping
flag = true;
}
}
// If There Is No Swapping, The Loop Will Break
if (!flag)
break;
}
}
public static void main(String[] args)
{
int[] zap = {3, 2, 5, 1, 4}; // The Array Values
System.out.println("Array Before Optimized Bubble Sorting:");
for (int n : zap)
System.out.print(n + " ");
Optimized(zap);
System.out.println("\nArray After Optimized Bubble Sorting:");
for (int n : zap)
System.out.print(n + " ");
}
}
Steps Of The Program:
- At first, the Array Values will be taken and shared with the Optimized() function as an argument.
- In that function, the array length will be extracted, and a Boolean Flag will be set to False by default.
- Now, two nested loops will iterate over the array and swap the elements for sorting.
- If there is any swapping, the Swap Flag will become True.
- At the end of the loop, if the swap flag is true (that means swapping happened), the loop will go on.
- If the Swap Flag is false (that means swapping did not happen), the loop will break as the array has now been sorted; that is why no more element swapping is going on.
Output:
Performance Comparison Between Bubble Sort Vs Insertion Sort:
In Java, there are many other sorting algorithms present. Among them, most students get confused between the Bubble Sort and Insertion Sort, as both of them work on a comparison-based technique.
To clear the differences, we will discuss the performance comparison between the Bubble and Insertion Sort.
Criteria | Bubble Sort | Insertion Sort |
Number of Swaps | More | Less |
Number of Comparisons | More | Less |
Practical Usage | Rare | Common |
Memory Usage | High | Low |
Suitable For | Teaching | Small Data Swapping |
What Are Some Advantages And Disadvantages Of Bubble Sort Algorithm?
Before further moving ahead, we would like to share some Advantages and Disadvantages of the Bubble Sort Algorithm which will clarify the concept more for you. Let us first start with the Advantages.
Advantages of Bubble Sort Algorithm:
- The Bubble Sort is the Simplest Algorithm among other Sorting Algorithms.
- The Bubble Sort can do In-Place Sorting. So, for the Bubble Sort, we don’t have to create any new space.
- The Bubble Sort Algorithm is a Stable Sorting Algorithm which preserves the order of equal elements.
- The Bubble Sort can easily detect if the array is already sorted or not.
Disadvantages of Bubble Sort Algorithm:
- The Bubble Sort does not apply to any Larger Dataset.
- Bubble Sort performs too many Comparisons and Swaps that take more time.
- The Bubble Sort can’t be used in any Competitive Exams to get programming results.
- The Bubble Sort Algorithm consumes more CPU time to swap elements.
Comparison Table Between Bubble Sort And Other Sorting Algorithms:
Along with the Bubble Sort in DSA, there are some other Sorting Algorithms as well. Let us check the differences between the Bubble Sort and Other Sorting Algorithms in the following Comparison Table.
Students often get stuck on sorting and other tricky topics, if you need help with your Bubble Sort implementation, we’ve got you.
Here, we are comparing them based on Speed, Efficiency, Complexity, etc. Criterias.
Criteria | Bubble Sort | Quick Sort | Merge Sort | Insertion Sort | Selection Sort |
Speed | Slow | Fast | Moderate | Slow | Slow |
Efficiency | Poor | High | High | Moderate | Poor |
Complexity | Simple | Complex | Complex | Simple | Simple |
Stability | Stable | Unstable | Stable | Stable | Unstable |
Memory Use | Low | Low | High | Low | Low |
Execution Time | 150-250 ms | 2-8 ms | 5-10 ms | 50-100 ms | 90-180 ms |
What Are Some Advanced Variations Of Bubble Sort Algorithm?
We all know that the Bubble Sort Algorithm is not that efficient. However, there are some Variations of the Bubble Sort Algorithm, which are a bit better in performance than the Normal Bubble Sort Algorithm.
Let us check the following list where we have discussed some Advanced Variations of the Bubble Sort Algorithm.
1. Cocktail Shaker Sort:
It is also called the Bidirectional Bubble Sort. Here, instead of Sorting in one direction, Sorting is done in both directions. So, the placement of Lower and Higher values is done quickly.
When To Use In Real-World Applications:
- In Graphical Visualization, the Cocktail Shaker Sort is used to get quick sorting of small data.
- For Real-time Data Processing where values change slightly over time, the Cocktail Shaker Sort is used.
- In Game Development, to sort scores or leaderboards, the Cocktail Shaker Sort is used.
2. Odd-Even Sort:
It is also known as the Brick Sort. In this Sorting Variation, the Array is divided into Odd and Even Index Values. Then, in those two divisions, the Bubble is created to Sort the Algorithm.
When To Use In Real-World Applications:
- In Parallel Processing, the Odd-Even Sort can be used as it can do Independent Comparison.
- We can use it in an Embedded System where Limited Hardware Capabilities are present.
- Mostly used in Educational Purposes as it helps to understand an Easy Sorting Method.
3. Recursive Bubble Sort:
In this case, instead of using the Iteration Method (Loop), we use the Recursion. However, this will not change the Time and Space Complexity. This is only used for Educational Purposes. Let us understand this with a simple code snippet.
public class Main {
public static void Recursive(int[] zap, int z) {
if (z == 1) // Implementation Of Base Case
return;
for (int i = 0; i < z - 1; i++) // Throwing One Pass Of Bubble Sort
{
if (zap[i] > zap[i + 1]) {
// Swapping The Elements
int t = zap[i];
zap[i] = zap[i + 1];
zap[i + 1] = t;
}
}
Recursive(zap, z - 1); // Recursively Calling The Function
}
- Here, a function is developed that will take the Array and its Number of Elements.
- Now, the Base Case will be developed that will check, if there is any item left or not.
- If the Base Case is False, then 1 Pair of Elements will be inserted in the For Loop. In that loop, the element swapping will be done.
- In the end, the function will again be called with the remaining part of the array.
What Are Some Common Mistakes With Java Bubble Sort Algorithm?
You might be eager to work with the Bubble Sort Algorithm as your concept is now cleared. However, before starting to implement the Bubble Sort Algorithm on your own, you should check some Common Errors that most of the students commit.
In the following list, we are going to mention some important Common Errors related to Bubble Sort.
- Oftentimes, we forgot to reduce the Inner Loop Range after each Iteration Pass. So, we should reduce the Inner Loop Range carefully.
- Sometimes, we forget to check whether the Array is already Optimized and Sorted or not. So, before performing Bubble Sort, we need to verify using Swap Flag.
- Sometimes, we modify the Original Array unintentionally which causes issues later. So, we should always create a Copy of the Original Array.
- Occasionally, we compare Elements in an Array with the wrong logic that brings errors. So, we should be careful with the Bubble Sort Logic.
- Sometimes, we used the Bubble Sort Algorithm for Large Dataset where it takes more time to complete. For Large Datasets, we can use Quick Sort, Merge Sort, etc.
Conclusion:
As we saw it is very important to know about the “Bubble Sort in Java”.
In the Bubble sort algorithm, the array concept is highly used. The array concept falls under the Data Structure Subject. So, the Data Structure needs to be very clear before moving to the Bubble Sort Algorithm in Java.
Also, it is advisable to clear the basic Java Programming before jumping to this topic. Some of the important sections like calling a function, and sharing an array as the argument are necessary to know to perfectly implement the Bubble Sort Algorithm in Java.
Takeaways:
- The Bubble Sort Algorithm is implemented with the help of the Iteration Process.
- The Best Case Time Complexity of the Bubble Sort Algorithm will be O(n).
- The Worst Case Time Complexity of the Bubble Sort Algorithm will be O(n2).
- The Space Complexity of the Bubble Sort Algorithm is not dependent upon the size of the Array.
- Odd-Even Sort and Recursive Bubble Sort are some Advanced Variations of Bubble Sort Algorithm.
