Java Performance Optimization: Tips and Techniques

Conducting a Java development project is pretty common these days. So what makes your product a cut above is how well optimized it is or how well it performs. Gone are the days when Java development projects were developed just for the sake of it; today, several tools and techniques are considered to optimize the code and enhance performance in very many ways.

Being one of the best programming languages across the globe, I no longer need to delve into the why part since you will come across several posts that emphasize using Java for your upcoming development project. So, what’s the issue? Well, unfortunately, the programming language has often been criticized in the context of performance. The following post mainly focuses on how to fine-tune Java performances. Here, you will find some of the most amazing techniques for maximizing Java speed and optimizing performances to a great extent.

Now, these are two things: write a code and write a clean, readable, and concise code that works effortlessly. So gone are the times when developers used to create an app that solves one or two problems; now the focus has shifted towards not just solving a couple of issues but also ensuring that the developed app is easy and pleasurable when it comes to use. In addition to all this fuss, there are times when you have so many projects lined up that you are unable to review the code due to numerous reasons, such as deadline constraints or budget. This is where we bug in. Here, further below, you will come across some of the best tips to optimize Java code’s performance.

Top Tips to Optimize Java Code’s Performance

1. Do not Write Long Methods

Now, there were times when it was believed that choosing the long method was the right thing to do. Well, fortunately, this no longer is the case. The method shouldn’t be long and should focus on a specific single functionality. By doing so, you can certainly enhance the app in terms of performance as well as support and maintenance. We all know that when we do class loading, the method is mainly loaded in stack memory. So what happens when these methods are large? Well, they consume so much memory as well as CPU cycles that it can be pretty difficult to execute.

As a solution, one is supposed to break the method into smaller ones, especially at suitable logic points. A quick advice: if you want to stay in the game for a long period, keep brushing up on your knowledge and skills again and again. This definitely can help you in being relevant.

2. The approach can be given a second thought

Development projects are all about trial and error. If one thing doesn’t work, you can surely put up with another. Also, there are times when developers have micro-optimization of a specific code path in mind. That is not completely wrong, but you need to think of the current coding choices. There are times when the fundamental approach isn’t the right thing to do. No matter how hard you try to put in effort and end up increasing the speed by 25%, things might not come as expected. So, all you have to do is try changing the approach, which can lead to a magnitude of improvement as well as a greater increase in performance.

So why does this happen? This happens when the scale of data is operated on changes. So try writing a solution that works well enough, but what happens when you get real data volumes and things start falling over?

public int findMax(int[] arr) {

int max = 0;

for (int i = 0; i < arr.length; i++) {

if (arr[i] > max) {

max = arr[i];

}

}

return max;

}

Now, this is a simple approach that looks fine when you have to deal with small arrays, but for large arrays, things might not work as expected, especially when the maximum value is near the end of the array. Here’s what you can do: divide the array into smaller sub-arrays and try to find the maximum value in each sub-array in a parallel manner. So this is how it will look.

public int findMax(int[] arr) {

int numThreads = Runtime.getRuntime().availableProcessors();

int chunkSize = arr.length / numThreads;

int[] maxValues = new int[numThreads];

Thread[] threads = new Thread[numThreads];

for (int i = 0; i < numThreads; i++) {

int start = i * chunkSize;

int end = (i == numThreads - 1) ? arr.length : (i + 1) * chunkSize;

threads[i] = new Thread(() -> {

int max = 0;

for (int j = start; j < end; j++) {

if (arr[j] > max) {

max = arr[j];

}

}

maxValues[i] = max;

});

threads[i].start();

}

for (int i = 0; i < numThreads; i++) {

try {

threads[i].join();

} catch (InterruptedException e) {

// handle exception

}

}

int max = 0;

for (int i = 0; i < numThreads; i++) {

if (maxValues[i] > max) {

max = maxValues[i];

}

}

return max;

}

As you can see, the code divides the array into smaller sub-arrays, which easily creates a separate thread to find the maximum value in each sub-array. So, the maximum values are mainly stored in an array and then combined to find the maximum value in the best manner.

Now, this approach has proven to be much faster, especially for tackling large arrays since here the concept of parallel processing is highly considered. So, in short, rethinking your approach can certainly give you an upper hand as well as the best possible outcomes.

3. Performance Testing

The next interesting Java performance optimization tip to consider is performance testing. This is a process to ensure that the subject of your developed app is realistic, or in case of any kind of extreme situations, it is easily possible to analyze how things perform. Some of the most popular options to consider here are Apache JMeter, Gatling, and BlazeMeter.

Now, I have come across many of you who tend to get confused between profiling and performance testing. Well, both concepts are different. Profiling can be described as looking closely at your favorite car and examining its core elements, whereas performance testing is said when you are riding the car and checking how it performs in different situations.

As soon as you have successfully conducted performance tests and identified certain errors, you need to use a profiling tool that can assist you in finding the underlying cause of these issues.

4. Prepared Statement

Java incorporates one statement that is highly considered for executing SQL queries. Statement class has a few flaws.

Connection db_con = DriverManager.getConnection();

Statement st = db_con.createStatement();

String username = "USER INPUT";

String query = "SELECT user FROM users WHERE username = '" + username + "'";

ResultSet resultset.executeQuery(query);

So when the developer enters - OR 1=1–

SELECT user FROM users WHERE username = '' OR 1=1 -- '

So what happens now is the query will return all records in the user’s table because the aforementioned condition 1 = 1 is always true. Now, you must be wondering why there is a double dash at the end of the comment. Well, it is the sole reason why developers need to ignore the original query. Unfortunately, statements are highly vulnerable to SQL injections, which is why PreparedStatement needs to be given importance. So, these are compiled statements for every new query. Unlike them, these can be reused a wide range of times each including a wide range of parameters, so changes as per your desire are quite possible.

5. Use StringBuilder

Now, I am sure that when we talk about concatenating strings programmatically, you will come across a wide range of options in Java. For example, use a simple + or +=, the good old StringBuffer, or a StringBuilder. However, things might go wrong. Wondering why?

The answer lies in the code that concatenates the string. Here, if you are planning to add new content to your string in a for-loop, try using a StringBuilder. This turns out to be one of the easiest ways to do so and gives you an upper hand when it comes to performance. Many developers end up using StringBuffer instead of StringBuilder. Well, in the end, it is not thread-safe and sometimes not the best fit for all use cases.

StringBuilder sb = new StringBuilder(“This is a test”);

for (int i=0; i<10; i++) {

sb.append(i);

sb.append(” “);

}

log.info(sb.toString());

By doing so, you will be able to develop a new Stringbuilder consisting of String and a capacity for 16 additional characters. So, once you start adding more and more characters, the JVM dynamically increases in terms of size. In simple words, the overall efficiency of the product is enhanced.

In and all, Java is a pretty powerful programming language, so nothing can stop developers from writing highly robust and scalable apps. Now, here, I would like to make you aware of the common issues that harm the performance of Java applications.

1. Object creation

Well, one of the common problems that can slow down a Java app’s performance is creating too many objects. This ultimately causes a significant performance hit. Whether it’s an object creation or garbage collection, things might be quite dreadful and tricky.

2. String operations

The next issue to take care of is string operations. Yes, strings are pretty immutable in Java, so whenever you try modifying a string, there a high chances that new string objects are developed. This does lead to the creation of performance bottlenecks, especially when you are dealing with tons and tons of data. Concatenating strings with the “+” operator is pretty common here.

3. Looping

Loops are pretty important; no two ways about it! However, there is no need for poorly optimized loops, which can impact performance. One of the most obvious mistakes is iterating over collections using the “for-each” loop, so this certainly creates an iterator object behind the scenes. In other words, it is an unnecessary object creation.

4. Regular expressions

This issue arises when you are mainly developing a search function featuring regular expressions mainly to match patterns irrespective of the dataset, small or large. Complex regular expressions can be highly resource-intensive and have an impact on overall performance, especially if the dataset is large.

Final Verdict

Java was, is, and will always be your best bet; there are no two ways about it. Fortunately, tech is here to stay for the long run, so why not make the most of the opportunities by incorporating the aforementioned techniques and approaches?

All the methods and techniques are clear to you. It doesn’t matter whether you are a techie or a non-techie, having a basic idea of how to conduct a successful development project is the pretty obvious thing to do, or else you might end up spending a fortune on your development project and get absolutely nothing out of it. So try to adhere to these practices, and nothing can stop you from releasing high-quality products, irrespective of your development approach.

I hope you found the following post worth considering. If you have any issues or concerns, feel free to get in touch, and we will surely get back to you. Also, it is advisable to hire a reputable and experienced Java development company that has the proper knowledge and experience to offer the best possible services in their space. Good luck with your upcoming development project.