Differences between JDK, JRE and JVM

JAVA DEVELOPMENT KIT

The Java Development Kit (JDK) is a software development environment used for developing Java applications and applets. It includes the Java Runtime Environment (JRE), an interpreter/loader (Java), a compiler (javac), an archiver (jar), a documentation generator (Javadoc) and other tools needed in Java development.

JAVA RUNTIME ENVIRONMENT

JRE stands for “Java Runtime Environment” and may also be written as “Java RTE.” The Java Runtime Environment provides the minimum requirements for executing a Java application; it consists of the Java Virtual Machine (JVM), core classes, and supporting files.

JAVA VIRTUAL MACHINE



It is:

Difference betweem JDK, JRE and JVM

To understand the difference between these three, let us consider the following diagram.

Note : JDK is only used by Java Developers.

  • JREJava Runtime Environment (to say JRE) is an installation package which provides environment to only run(not develop) the java program(or application)onto your machine. JRE is only used by them who only wants to run the Java Programs i.e. end users of your system.
  • JVMJava Virtual machine(JVM) is a very important part of both JDK and JRE because it is contained or inbuilt in both. Whatever Java program you run using JRE or JDK goes into JVM and JVM is responsible for executing the java program line by line hence it is also known as interpreter.
  • How does JRE and JDK works?

    What does JRE consists of?
    JRE consists of the following components:

    How does JRE works?
    To understand how the JRE works let us consider a Java source file saved as Example.java. The file is compiled into a set of Byte Code that is stored in a “.class” file. Here it will be “Example.class“.


    The following diagram depicts what is done at compile time.

    The following actions occur at runtime.

    How does JVM works?

    JVM becomes an instance of JRE at runtime of a Java program. It is widely known as a runtime interpreter.JVM largely helps in the abstraction of inner implementation from the programmers who make use of libraries for their programmes from JDK.
    For detailed working of JVM click ->Working of JVM

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