How to Improve Java Performance? 8 Proven Ways

Programming can be described as a conversation with a computer. By creating consecutive lines of code, programmers communicate commands which are to be executed. However, it isn’t easy to count on the results without an appropriate language, which will be understandable for both sides. One of such languages is Java – practically the most popular programming language, with versatile use.

How to improve Java performance? What to do to make a program written in Java work faster? What tools to use to monitor Java performance? You will read about it in the next part of the article.

Most important Java application performance problems?

Write once, run anywhere – this is a slogan that dates back to 1995, and that perfectly illustrates the capabilities of Java. That programming language is fast, secure, and reliable. That’s why it’s widely used – we can even say that Java is everywhere and accompanies us in everyday life. However, as with any programming language, performance is a significant issue in the case of Java.

There are many reasons for poor Java performance. From poorly executed design and poor-quality Java code to the efficiency of local hardware such as RAM and CPU cycles to network bandwidth and database connections. Java application performance is also affected by operating system issues. One must always be aware that there is a communication gap between the intentions of the human (both the person ordering the application and the programmer) and the computer.

data access framework properly


Why is my Java program so slow? The reasons of performance issues in Java

Now, let’s take a closer look at factors that cause the performance of Java applications to be reduced.

1. Databases

The database is the core of an application’s functionality. So, a lot depends on it, which can also become a source of severe performance problems. To avoid them, you should pay attention to eliminating any slow queries to the database. In fact, interaction with the database is best when it is asynchronous and takes place through write. Java performance will also be improved when the database is used to back up data and retrieve static data at application startup. From a business perspective, you should know that performance issues in the database context most often occur as the application load increases. So, it’s worth thinking in advance about the link between business transactions and database calls.

2. Caching

When analyzing Java performance problems, one cannot forget about caching. Java application performance largely depends on its purpose, i.e., the type of tasks it has to perform. Further, it is essential what those tasks are related to, e.g., whether it is necessary to perform many complex calculations, which translates into the use of CPU power, or whether it is required to write and read a lot of data, which translates into the efficiency of input/output operations and performance of related devices.

Although the idea of caching is focused on improving Java performance, it should also be realized that the load on a given system is also reduced by using caching. The time required to perform a given operation is usually the cost of performing that operation. Therefore, speeding up processes using cached data reduces the load on limited resources.

3. Memory

You might think we can forget about memory management altogether, but not really.

Java has a garbage collector that takes care of memory management for us. A common problem that affects performance is memory leaks. A memory leak occurs when given objects are no longer used by the application, but the garbage collector cannot remove them because our application still stores references to them. As a result, more and more resources are consumed, significantly slowing down our application until they run out and the OutOfMemoryError is displayed.

However, the lack of OutOfMemoryError is not synonymous with the fact that we do not have a memory leak. A memory leak can occur without any reported errors. It simply ends up with our application performance dropping dramatically due to excessive garbage collector work.

Memory leaks do not show up in an obvious way. Instead, they are usually detected during a careful code review or with the help of debugging tools known as heap profiler. That’s why it’s a good idea to learn more about it and prevent such situations beforehand.


How do I make my Java program run faster?

The Java applications that enjoy popularity and recognition are those that are fast and useful.

Today, most users place just such demands on applications and programs. It is not surprising – we live in a digital age and expect uncomplicated and fast access to information, the ability to shop online, efficient work or seamless social interaction.

In the performance context, it is worth paying attention to the three elements described above. Additional problems are poor design guidelines and low code quality. Although Java is one of the most intuitive programming languages, it doesn’t mean that everything you try to code in it will be readable by computers.

So, if you are looking for an answer to what to do to make your Java application run faster, first of all, think about the performance problem by design.

A good team of programmers experienced in Java will indeed point out possible ways of optimization. From the customer’s point of view, it is crucial to define expectations about the functionality of the application clearly. By combining these elements, you have a real chance to create an efficient, valuable and fast Java application.

An example of this is created by Stratoflow’s team high-performance, horizontally scalable cloud platform for financial applications, system of flight schedule or travel search engine handling 300 million queries daily.

performance test suite


8 proven ways to improve Java performance

1. Use the latest version of Java

Each subsequent release of Java includes key performance enhancements. So, when you want to take care of Java application performance, make sure you are working with the latest stable version of Java so you can implement best practices into your project.

The latest Java patches have key enhancements that directly improve application performance, memory consumption, stability, and security. Using an up-to-date version of Java ensures that your Java applications will continue to work with the latest releases.

2. Avoid writing long methods

A method is nothing more than an element that groups a set of instructions. The code should be grouped in this way in a situation where its fragment has to be implemented in many places.

Then it is much better to create a method and run it than to copy the same piece of code many times. Methods also work well when the programs are extensive, whereas mastering the entire project would be very time-consuming without proper division.

The sensible division into smaller parts allows for understanding the code faster. It is important to remember that if methods are too large, they require much processing. Thus, their execution consumes both memory and CPU cycles, negatively influencing the application performance.

3. If-else statements optimization

The “if” statement in Java is the simplest form of decision-making statement. This “if” statement helps us define some conditions. Based on these conditions, we determine some lines of code to execute.

Unfortunately, using too many if-else conditional statements can affect performance because the Java virtual machine will have to compare the conditions. In case there are too many conditions in the business logic, it is a good idea to group them. To improve performance, you can also use switch statements instead of multiple if-else conditional statements.

4. Use primitive data types as often as possible

Java offers eight primitive types ‒ boolean, byte, short, int, long, float, double, and char. These are the building blocks from which complex types, defined by programmers, are composed.

Proper selection of primitive types instead of their wrapper classes allows the JVM to store the value on the stack instead of the heap. This reduces memory usage and increases performance.

5. Use PreparedStatement instead of the Statement

PreparedStatement is an extended and powerful version of the instruction interface that may or may not be parameterized, meaning, unlike instructions, it can take input parameters that take faster performance into account.

It also helps you write object-oriented code with set methods that improve application performance. And the best part is that it is executed using a binary communication protocol other than SQL, which is essentially a non-text format used to communicate between clients and servers, which ultimately reduces bandwidth usage, thus promoting faster server connections. So, when tuning Java, this position should not be missing from the to-do list.

6. Optimize only when necessary

To improve Java application performance, you must remember one fundamental rule – it’s not worth sacrificing good design for performance.

It’s better to write valuable programs than fast ones. If a program is not efficient enough, its architecture will allow for optimizing it later. Good programs follow the principle of data encapsulation, so individual decisions can be changed without affecting the rest of the system.

This also does not mean we should ignore performance problems until we finish the program. Implementation problems can be fixed by later optimization, but pervasive performance-limiting architecture flaws may not be fixable without rewriting the entire system from scratch.

When we do “clever things” with code to speed it up, it’s not uncommon to have to make compromises. More often than not, this means that we introduce instability. The code may run faster, but it’s more likely that it won’t run as we expect it to for all test cases.

7. Use profilers to identify bottlenecks

Another important point when tuning Java is to use profilers.

There comes a day in every programmer’s life when it turns out that the written code is not entirely efficient and needs to be sped up. Therefore, it is worth using a profiler to find the weak link in the following lines of code. Then you know which areas need improvement and can increase the performance of Java applications.

8. Logging

The importance of logging when writing code, especially in maintenance, cannot be overstated.

Every Java programmer who has ever debugged production code has probably wished for more logs. There are many logging libraries and frameworks in Java, including SLF4J and Logback. While they make logging in your code base relatively simple, you should make sure you follow logging best practices.

When tuning Java, avoid excessive logging and only include information that can be useful for troubleshooting. Use external tools to track, aggregate, and filter logging messages for faster analysis.


Best Java performance monitoring tools

We already know the most common causes of Java performance problems and how to improve them.

Information about Java monitoring applications is also helpful in this context. Nowadays, using technology, applications are becoming more complex and distributed. Therefore, it is necessary to monitor their performance and load testing to provide better satisfaction to the end-user.

At Stratoflow, we are specialists in high-performance Java. Our programs can process a vast amount of data in a short time so that the business solutions offered to clients are not slowed down. In our everyday work, we develop Java-based applications and services and take care of their performance optimization as well as load testing. Without best Java application performance monitoring tools, application performance management, performing comprehensive analyses would be difficult.

Profilers are particularly useful for this kind of work – including Java VisualVM, Oracle Java Mission Control and NetBeans Profiler. They provide a comprehensive view of all JVM metrics and also support detailed memory analysis.

Also worth mentioning are lightweight Java profilers like xRebel and LightStep, which track the performance of individual web requests or transactions while allowing you to test connections, and group and filter data in a user-friendly interface.

Verifying how Java applications perform live in a production environment is also essential. APM (Application Performance Monitoring) tools help with this.

Thanks to them, it is possible to test in a controlled environment particular application functions and verify their overall performance before releasing them on the market. This way, key errors are eliminated from the end user’s point of view, affecting their satisfaction level and the business’s profitability.

Popular tools include Glowroot, Pinpoint, JavaMelody, Scouter, Stagemonitor or MoSKito.

Besides, tools for monitoring real users (RUM), analyzing Java logs and application memory and leaks like Eclipse MAT are helpful.

Performance of Java apps – boost your business!

The popularity of Java applications is not decreasing, hence the constant demand for Java developers. However, to make this one of the most popular programming languages in the world useful and contribute to the development of your business, you need the knowledge and experience of those who create applications and services.

With their support, you can create high-performance tools that support companies and are helpful to users, which in the digital age is a competitive advantage and increases the chances of a profitable business.

In Stratoflow, we firmly believe that effective communication is key in delivering complex software projects. That is why we provide our clients with the support of highly specialized dedicated teams.This allows us to create high-performance Java applications and programs capable of processing vast amounts of data in a short time. As a result, the solutions designed for our customers contribute to their business development.

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