jRebel - What is it and what should developers know?

jRebel is a Java development tool that was formerly known as JavaRebel. This tool removes the need to redeploy the code as it will immediately change the codes and you need not restart the system. The tool is especially helpful while executing a tricky logic which you want to get right. For instance, if you want to add an approval to your structure, with the help of jRebel you can include the rules in fields, one after the other. You can keep working on the errors until the structure has been perfected. In addition if you have to add more fields to the controller or manager, you can do that too without any difficulties. jRebel will save all the application states. This factor ensures that it does not matter how you are arriving at the page you want to alter.



Things Developers Should Know About jRebel

jRebel uses the JVM, a Java agent plugin, which is a command for line option. It is easily downloadable from Java. This tool utilizes it for installation. However, do not misinterpret jRebel as an IDE plugin. Although there are certain modifications that the developers can carry out with it for a better experience but jRebel can work equally efficiently with a vanilla Java compiler and text editor. It would also be helpful for the developers to know that this is not a framework either. An application is not dependent on it. Developers can remove it anytime they want and continue with their work without any hindrance. Finally, there is no need to make any alterations to JVM while developing with this tool. It is compatible with all the major JVM implementations.

How It Works

Developers will have to integrate the tool with applications servers and JVM at the class loader level. However, instead of creating of new ones, it will extend the existing ones so that they can manage the reloaded classes. Once a class is loaded, the tool searches for an equivalent .class file from the classpath and other places that are mentioned in the rebel.xmlconfiguration file. When it finds the file it is searching for, the instruments will match it with the found.class file. The .class file is monitored as the changes are made in the loaded class. The updates are produced via extended class loader to the application. If mention in rebel.xml, it can also scrutinize .class files.

The developers can especially benefit from the fact that jRebel keeps the existing instances of the class while loading updates to it. This not only enables the application to keep running but it also does not go for a rerun when a new field is introduced.

If the programmers are using this tool then debugging gets a better solution. While chasing a bug, you research on what is happening, make changes and implement them and the effects will be shown immediately. Next time when such problems arise, the new code will break in directly once it has completed assembling the code.

Benefits of Using jRebel

There are various reasons why jRebel is used and the developers should be aware of it in order to apply this tool properly. This can be used to test and try the features of a framework together. Short codes to test the functionality of a new system can be included and the results will show immediately. The developers can also make use of the library to look for codes and install the same in the applications. Even in situations when owing to performance issues or diverse networks, the system cannot be stimulated, jRebel enables system deployment on the developer’s computer.

In addition to these, there are no restarts or intervention from this tool. This provides the developers with more chances and time to check if all is going well. They also have more time to improve things. To ensure scalability, performance and robustness, jRebel is the most convenient Java development tool available presently. To get maximum benefits of Java development, you may consider hiring services of a Java application development company.

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