What Is JRebel?

Fifty-nine percent of developers surveyed in the 2021 Java Developer Productivity Report say they spend four minutes or more on redeploy times. Over the course of a year, this results in hundreds of hours lost. With JRebel, you and your team can bypass these wait times and spend more time coding. Read on to see how JRebel works and why developers choose this Java tool.

What Is JRebel?

JRebel is a productivity tool that allows developers to reload code changes instantly. JRebel skips the rebuild, restart, and redeploy cycle common in Java development.

JRebel enables developers to get more done in the same amount of time and stay in the flow while coding. Give your developers back their time so that they can maintain a constant flow as they develop their application. JRebel supports a majority of real-world enterprise Java stacks and is easy to install into existing development environments.

JRebel is a JVM plugin and not an IDE plugin, framework, application server, or custom JVM. JRebel is often used through an IDE like IntelliJ and Eclipse but can be used without an IDE. JRebel does not introduce any dependencies in your application, and does not require you to make any changes to the JVM.

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How JRebel Works

JRebel instantly reloads changes made to a class structure, making a full app redeploy unnecessary. You just save, refresh, and see the changes right away. To achieve this, it does not wrap classloaders around classes, but patches existing classloaders to make classes loaded through them reloadable using instrumentation.

JRebel tracks changes that you make in your workspace, and updates them as you go, so you can keep focused on the code and stay in the zone without interruption.

JRebel and Your Development Stack

JRebel exists as a JVM plugin. With support for over 100 frameworks, and many popular application servers, IDEs, and JVM languages, JRebel works out of the box for almost every stack.

JRebel and Your IDE

JRebel does not depend on any IDE or development tools in particular (besides a compiler). However, JRebel has IDE plugins for all of the main Java IDEs available for Java developers. Explore installation for the top Java IDEs:

• JRebel for Eclipse
• JRebel for MyEclipse
• JRebel for IntelliJ IDEA
• JRebel for NetBeans
• JRebel with IBM WebSphere & Rational (RAD)
• JRebel with JDeveloper

View all supported JVMs, IDEs, application servers, and frameworks.

Why Use JRebel?

Time is money, and with JRebel, you can save both. JRebel saves the average Java developer over 150 coding hours per year. With the average developer spending five hours coding per day, that means over 30 coding days added back to your development cycle.

“Time is the most critical parameter in development, and JRebel saves us development time every day.”
— Software Architect at Intrasoft

Developers choose JRebel for the ability to:

• View changes in real-time—No more waiting for redeploys; you can see the impact of your code changes instantly with JRebel.
• Receive a high return on investment—Get a proven, high-ROI productivity tool that can immediately save your company time and money.
• Maintain application state—Stay focused on creating groundbreaking Java applications while maintaining application state.
• Integrate quickly and efficiently—JRebel is highly integrable, supporting over 100 of the top Java tools.

In addition, JRebel offers dedicated, professional support to ensure you can integrate quickly and troubleshoot effectively.

JRebel and XRebel

JRebel and XRebel exist as a single plugin to your favorite IDE. XRebel is a profiling tool that allows developers to trace the impact of their code from beginning to end—even in distributed applications. With XRebel, developers can easily identify and fix performance issues during development, accelerating time to market.

These two tools together save over 5,000 customers hundreds of hours of development time and lets them push their product to market that much sooner. Why not give it a shot? Try JRebel free for 10 days and/or try XRebel free for 10 days.

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Additional Resources

Curious to see how JRebel works for your stack specifically? Sign up for a personalized demo. You can also calculate the time and financial savings of JRebel based on your technology using our ROI calculator.

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This post was originally published on December 2, 2016 and has been updated for accuracy and comprehensiveness.