Java Runtime Environment (JRE)

JRE stands for Java Runtime Environment which is used to provide an environment at runtime. It is the cause of implementation of JVM (as discussed earlier). It contains a set of supporting libraries in combination with core classes and various other files that are used by JVM at runtime. JRE is a part of JDK (Java Development Toolkit) but can be downloaded separately.

JRE is a set of software tools for the development of Java applications.

You need JRE to execute your program, which includes two things:
  • JVM
  • Java Library
    • Static - Functions that are required at compile time.
    • Dynamic - Functions that are required at runtime and not at compile time.

In detail, the JRE consists of various components; these are listed below:

  • Java Web Start and Java Plug-in.
  • User Interface Toolkit, which includes Abstract Window Toolkit (AWT), Swing, Image Input / Output, Accessibility, drag, and drop, etc.
  • Other different base libraries, including Input/Output, extension mechanisms, beans, JMX, JNI, networking, override mechanisms, etc.
  • Lang and util base libraries which include lang and util, management, versioning, collections, etc.
  • Integration libraries, which includes Interface Definition Language (IDL), Java Database Connectivity (JDBC), Java Naming and Directory Interface (JNDI), Remote Method Invocation (RMI).

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