7 Java Profiling Tools That Will Skyrocket Your Productivity

Writing code correctly is important, but it’s equally crucial to understand how it performs in a real environment. To get a better sense of what happens internally, Java profiling tools can significantly streamline this process. While you may need to dedicate some extra time to profiling, it will ultimately save you a great deal of time that would otherwise be spent debugging without the help of these tools.

Java profilers provide valuable insights into CPU usage, memory allocation, thread execution, and much more. Different tools offer various types of insights, which we’ll explore in this article.

A Java profiler is a tool that helps you monitor the performance of your Java program. It tracks when objects are created, when methods are called, how many times loops run (including recursive calls), how threads are executing, and when memory is cleaned up. By analyzing how your Java code behaves within the system it’s running on, profilers help identify performance issues and areas that could be optimized.

What are Java Profiling Tools?

Profiling is an essential optimization step. This helps you in getting valuable insights into the behavior of your code as well as various performance metrics. When you understand your application, you can better pinpoint its areas for fine-tuning and thus improve its efficiency.

At its core, profiling reveals a problem that may influence the performance. For example, profiling assists in identifying slow running methods or excessive memory usage, and so on. So, these tools can highlight the bottlenecks and lead towards finding ways to optimize their performances.

Profiling often plays a key role in improving both application performance and overall system health. When speed is the issue, not only do profilers improve performance but also accelerate the development process by identifying and addressing inefficiencies early.

There are several types of profilers. You probably are asking why there are such various kinds of profilers since the standard JVM profilers exist. The answer is easy: one tool is too weak. In the high-tech world, there’s no golden hammer.

For instance, you may be required to concentrate on a specific area, say CPU usage or detecting memory leaks. Conversely, if you are looking for a general overview of how your application is performing, then you require a mix of tools that give you the right insight.

So, which profiler fits your bill? This article will help you navigate and make your choice.

Below, we’ve listed some of the most popular Java profilers that can streamline the profiling process and are widely used by Java developers.

1. JVM Tools

These are tools that come with the Java Development Kit (JDK) and are used to monitor and improve the performance of Java programs. You don’t need to install anything extra to use them. Here’s a simple explanation of each tool:

jstat: This tool helps you monitor how Java is using memory and handling things like garbage collection (the process of cleaning up unused memory). You can use it through the command line to check things like memory usage for your Java program.

jmap: jmap shows detailed information about the memory used by a Java program, such as how much space objects are taking up. It helps you understand memory usage better and can even create a snapshot (dump) of the memory to analyze later.

jcmd: This tool sends commands to the Java Virtual Machine (JVM), such as asking it to generate a memory dump. It’s useful for diagnosing problems with how the Java program is running.

jhat: jhat helps you explore the memory snapshot (heap dump) created by tools like jcmd. It helps you look at the objects in memory and find issues like memory leaks, where objects are stuck in memory even though they’re no longer needed.

hprof: hprof records detailed information about how your Java program is using memory and CPU. It helps track performance issues like slow memory usage or excessive CPU consumption. You can use it to gather data on how much memory different parts of your program are using or to find performance bottlenecks.

2. VisualVM

It is lightweight and can be used during development and production. It automatically detects and lists Java apps running on your computer or remote systems (as long as the jstatd service is running on the remote machine). If an app isn’t automatically detected, you can add it manually using a JMX (Java Management Extensions) connection.

It provides detailed information about each Java process, including the process ID (PID), main class, JVM version, JDK path, JVM flags, and system properties. VisualVM also tracks performance metrics like CPU and memory usage, garbage collection, and the number of threads running.

For deeper analysis, you can take thread dumps to see what’s happening inside your app or create heap dumps to identify memory leaks. If an app crashes, VisualVM helps analyze core dumps to diagnose issues related to threads and memory.

Additionally, VisualVM allows you to save this data-thread dumps, heap dumps, and performance information-into a single file for offline analysis.

In short, VisualVM is a powerful tool that helps you monitor, debug, and optimize your Java applications effectively.

3. Java Mission Control and Java Flight Recorder

Java Mission Control (JMC) and Java Flight Recorder (JFR) are sophisticated profiling tools designed for high-performance Java application monitoring. They are especially valuable in a production environment where low overhead is crucial, as JMC provides very detailed insights into application behavior with minimal performance impact.

JFR captures very detailed runtime events that would help to produce information necessary for performance tuning. This is how application performance can be deepened by revealing bottlenecks and potential optimization points. Being an event-driven mechanism for data collection, JFR does not require much system resource. Therefore, it can continuously monitor in live systems.

Main advantages of using JMC and JFR include the following:

Low overhead in production environments

High-resolution collection of performance data

Deep analysis capabilities in JVM and application performance

Historical data to support more accurate troubleshooting

By using JMC with JFR, developers can analyze comprehensive system behavior and performance of the threads efficiently. This potent combination is indispensable for broad performance diagnostics and real-time monitoring. It can hugely enhance the understanding and optimize the Java application.

4. YourKit Java Profiler

YourKit Java Profiler monitors and improves your app performance by showing you what’s going on with its threads-those parts of your application that run in parallel. If a thread gets stuck, the profiler quickly alerts you and shows you which threads are blocked and why.

It also lets you see how things like web requests (HTTP) and database queries (SQL) are being handled by your app, so you can get a full picture of performance.

The profiler makes it easy to track how your app is using CPU, memory, and handling things like garbage collection (cleaning up unused memory). If your app is throwing a lot of exceptions (errors), it will quickly show you where they’re happening.

YourKit also supports obfuscated apps, hidden or renamed for protection, by tools such as ProGuard or Allatori. You should be able to obfuscate your mod file and it will display the original names of things in your code.

It also collects performance data, so you can control how much data it collects, which will not slow down your app too much. It is so efficient that you can use it in production. It even lets you export the data in various formats so you can share or analyze later, and you can automate it for continuous monitoring.

Furthermore, it also has a flexible API, which means developers can create custom features and command line tools to do profiling tasks without the UI. There are different licensing options, including free licenses for open-source projects and discounts for schools and research groups.

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