JRE stands for Java Runtime Environment, every code requires some environment to be compiled and executed. This is where the JRE comes into the picture for java codes. When Java codes are compiled, they are converted to Byte Code which is then transferred to the Java Virtual Machine which applies the .class extension to this and executes the program. JVM is included in JRE.
Java Development Kit (JDK) combines all of these JRE, JVM, libraries, etc. Any system that has JRE can run a java program. Although JVM is not a particular software or you will not get any real file of it but it is associated with the physical component of JRE. We just need to install JDK and that will be enough to compile and run any Java code.
The Java Virtual Machine performs the following functions:
- Loads Code
- Verifies Code
- Executes code
- Provides runtime environment
Purpose of Java Runtime Environment
Whenever a program is sent for execution, the Java Runtime Environment combines the libraries and JVM to compile the program and build the Byte Code. It combines all the resources for the execution of the program. It actually exists as an implementation of Java Virtual Machine.
It can be summed up and said JRE = set of libraries + other files that JVM uses at runtime.
JRE consists of some popular developmental tools which help to create applications easier. Some of the tools are:
- Standard JDK Tools and Utilities
- Javac, Javadoc
- Internalisation tools
- Remote methods
- Java development tools
- Java plug in tools
- Java web start tools
Why to use Java Runtime Environment?
Well, for developers, JDK is most important, as it will also include JRE and other classes but if we have to just run some program in java then we can use only JRE for the purpose. We do not need to install the heavy development kit rather we can just install JRE.
Installation of Java Runtime Environment
If you want to install JRE in your local environment then follow the below steps:
- Browse to Java SE Runtime Environment 9 download page and choose the JRE installer.
- Download any of the latest JRE installers.
- Click on Accept License Agreement and then select the corresponding windows version and install it.
You can also checkout the official JRE documents on the link.
Frequently Asked Questions
JRE provides the basis for execution of a java program, without it any Java code cannot be executed.
Yes, Installing JDK is much better for developers as it also includes JRE and other classes for programme execution.
JVM is not a physical program like JRE or JDK, but it is associated with JRE and JVM will always require the recourses compiled by JRE to execute a programme.
Java plays a vital role in most application development in these days and hence JRE will always come into picture for the execution of any Java program. Even now billions of devices use Java for their primary functionalities, JRE being an essential component of the Java Development architecture.
Hope this article is useful to aspiring developers and programmers.
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By Aniruddha Guin