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1. JAVA RUNTIME ENVIRONMENT 11 SOFTWARE
2. JAVA RUNTIME ENVIRONMENT 11 CODE
3. JAVA RUNTIME ENVIRONMENT 11 SERIES
4. JAVA RUNTIME ENVIRONMENT 11 DOWNLOAD

As a developer, you'll mostly work with the JDK and JVM, because those are the platform components you use to develop and run your Java programs.

JAVA RUNTIME ENVIRONMENT 11 SOFTWARE

While there is a conceptual side to the JRE, in real-world practice it's just software installed on a computer, whose purpose is to run your Java programs. A layered architectural view shows that the JRE contains the JVM, class loader, and Java class libraries. From a package perspective, the JRE contains the JVM, as shown in Figure 2. The JVM is part of the JRE-it's the active, running part that the JRE creates to host programs. The JRE takes static assets and turns them into a running JVM hosting the running program. In the layered view I just described, the JVM is created by the JRE.

JAVA RUNTIME ENVIRONMENT 11 CODE

This important piece of software loads compiled Java code into memory and connects the code to the appropriate Java class libraries (a process known as linking). As an example, the Java class loader is part of the JRE. The JRE contains libraries and software that your Java programs need to run. The JRE is the on-disk software component that takes your compiled Java code (the code is compiled with the JDK), combines it with the required libraries, and starts the JVM to execute it. It's a classic example of abstraction, abstracting the underlying operating system into a consistent platform for running Java applications.Ī Java virtual machine is a running software system responsible for executing live Java programs. In short, the JRE is a sort of meta-OS for Java, along with other JVM languages like Scala and Groovy. Automatic memory management is one of the JRE's most important services, ensuring that programmers don't have to manually control the allocation and reallocation of memory. The JRE smooths over the diversity of operating systems, ensuring that Java programs can run on virtually any operating system without modification. IDGįigure 1. The Java Runtime Environment spawns a JVM. The Java Runtime Environment spawns a JVM, which is a software layer that runs on top of a computer's operating system, providing additional services specific to Java. Each layer provides services that will be used (and required) by the layers above it.

JAVA RUNTIME ENVIRONMENT 11 SERIES

We can look at software as a series of layers that sit on top of the system hardware. Today, it's been adopted as a norm for many software systems, including JavaScript and Python. When it was first introduced, Java's "write once, run anywhere" principle was considered revolutionary. The JRE loads class files and starts a virtual machine (the JVM) that ensures there is access to memory and other system resources in a consistent form across many operating systems. In the case of Java and other JVM-based languages, the JRE creates an intermediary between the operating system and the actual program. The Java Runtime Environment changed all that, at least for Java programs. The program ran inside whatever computer it was on and relied directly on operating system settings for resource access resources like memory, disk access, and network access. In the past, most software used the operating system (OS) as the runtime environment. What is a runtime environment?Ī software program needs to execute, and to do that, it needs an environment to run in. Defaults work well for most implementations, especially when you're starting out with Java.

JAVA RUNTIME ENVIRONMENT 11 DOWNLOAD

You also can download the JRE separately from the JDK, and you may choose from a variety of JVMs. We'll dig a lot deeper into how these components work together in the discussion that follows.įrom an installation perspective, anytime you download a JDK, it will include a version-compatible JRE, and that JRE will include a default JVM. The JRE is mainly a container for those other components, and is responsible for orchestrating their activities.