What is java programming environment

What are JVM, JRE and JDK?

In this article, you will understand the differences among JVM, JRE and JDK. As a Java programmer, you should understand these basic stuffs clearly. It’s like you should see the characteristics and personality of your girlfriend or partner.

1. What is JVM?

JVM stands for Java Virtual Machine. It is an abstract computing machine that is responsible for executing Java programs. When you write a Java program, the source code is compiled into byte code which is understandable by the JVM. Upon execution, the JVM translates byte code into machine code of the target operating system.

The JVM is the cornerstone of the Java programming language. It is responsible for the very well-known feature of Java: cross-platform. That means you can write a Java program once and run it anywhere: Windows, Linux, Mac and Solaris, as long as JRE is installed on the host operating system.

Every time you run a Java program, the JVM is started to execute and manage the program’s execution. The JVM is running in two modes: client (default) and server.

An Oracle’s implementation for JVM is called Java HotSpot VM.

2. What is JRE?

JRE stands for Java Runtime Environment. It provides the libraries, JVM and other components necessary for you to run applets and applications written in the Java programming language.

The JRE contains standard tools such as java, keytool, policytool,… but it doesn’t contain compilers or debuggers for developing applets and applications.

3. What is JDK?

JDK stands for Java Development Kit. It’s a superset of JRE. The JDK includes the JRE plus command-line development tools such as compilers (javac) and debuggers ( jdb ) and others (jar, javadoc , etc) that are necessary or useful for developing applets and applications.

Therefore, as a Java programmer, you have to install JDK as a minimum requirement for the development environment.

• JVM: is the virtual machine that runs Java applications. The JVM makes Java platform-independence.
• JRE = JVM + standard libraries: provides environment for executing Java applications.
• JDK = JRE + development tools for compiling and debugging Java applications.

Okay, so far I have covered the basic information about the 3 cornerstones in Java programming: JVM, JRE and JDK. I hope you are now able to identify the differences among these components.

• You should have both JRE and JDK installations (setup) on your computer. You will need both during the development process.
• You should have multiple versions of JDK and JRE installed: 1.5, 1.6, 1.7 and 1.8 for different testing purposes in the future.
• You should install both 32-bit and 64-bit versions.
• When installing the JDK, remember to check ‘Install Demos and Samples’. Then you can explore various interesting examples in the demo directory under JDK’s installation path.
• Only the JDK includes source code of the Java runtime libraries. You can discover the source code in the src.zip file which can be found under JDK’s installation directory.

4. Where to download JRE and JDK?

The starting point is java.oracle.com, but you can go directly to this: http://www.oracle.com/technetwork/java/javase/downloads/index.html.

5. Where to find further information?

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About the Author:

Nam Ha Minh is certified Java programmer (SCJP and SCWCD). He started programming with Java in the time of Java 1.4 and has been falling in love with Java since then. Make friend with him on Facebook and watch his Java videos you YouTube.

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What is java programming environment

Java is a recently developed, concurrent, class-based, object-oriented programming and runtime environment, consisting of:

Java has the following characteristics:

• Object oriented — Java provides the basic object technology of C++ with some enhancements and some deletions.
• Architecture neutral — Java source code is compiled into architecture-independent object code. The object code is interpreted by a Java Virtual Machine (JVM) on the target architecture.
• Portable — Java implements additional portability standards. For example, int s are always 32-bit, 2’s-complemented integers. User interfaces are built through an abstract window system that is readily implemented in Solaris and other operating environments.
• Distributed — Java contains extensive TCP/IP networking facilities. Library routines support protocols such as HyperText Transfer Protocol (HTTP) and file transfer protocol (FTP).
• Robust — Both the Java compiler and the Java interpreter provide extensive error checking. Java manages all dynamic memory, checks array bounds, and other exceptions.
• Secure — Features of C and C++ that often result in illegal memory accesses are not in the Java language. The interpreter also applies several tests to the compiled code to check for illegal code. After these tests, the compiled code causes no operand stack over- or underflows, performs no illegal data conversions, performs only legal object field accesses, and all opcode parameter types are verified as legal.
• High performance — Compilation of programs to an architecture independent machine-like language, results in a small efficient interpreter of Java programs. The Java environment also compiles the Java bytecode into native machine code at runtime.
• Multithreaded — Multithreading is built into the Java language. It can improve interactive performance by allowing operations, such as loading an image, to be performed while continuing to process user actions.
• Dynamic — Java does not link invoked modules until runtime.
• Simple — Java is similar to C++, but with most of the more complex features of C and C++ removed. Java does not provide:
  • Programmer-controlled dynamic memory
  • Pointer arithmetic
  • struct
  • typedef s
  • #define

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  What is the Java programming environment?

  Of the three development environment environments, the JDK was by far the most successful. CodeWarrior and Visual J++ are examples of integrated development environments. That is, they include a text editor, an interactive debugger, a compiler, and tools for managing large programming projects.

  What are the basics of a typical Java environment?

  Java programs normally go through five phases—edit, compile, load, verify and execute.

  What is Java Runtime Environment and do I need it?

  The Java Runtime Environment (JRE) is what you get when you download Java software. The JRE consists of the Java Virtual Machine (JVM), Java platform core classes, and supporting Java platform libraries. The JRE is the runtime portion of Java software, which is all you need to run it in your Web browser.

  What are the four technologies in Java programming environment?

  About the Java Technology

  What is the benefit of Java?

  Java is object-oriented. This allows you to create modular programs and reusable code. Java is platform-independent. One of the most significant advantages of Java is its ability to move easily from one computer system to another.

  Why bytecode is called bytecode?

  The name bytecode stems from instruction sets that have one-byte opcodes followed by optional parameters.

  What is Java basic concept?

  Java Concept. … Java is a case-sensitive programming language, like C++. Java is an Object-Oriented Programming (OOP) structure. Java is a class-based programming language. Java technology is used for developing both, applets and applications.

  What are the elements of Java programming?

  Basic elements of a Java program include:

  • The main method.
  • Reserved words.
  • Special symbols.
  • Identifiers.
  • Data types.
  • Expressions.
  • Input.
  • Output.

  Does Windows 10 need Java?

  No, Java is not routinely needed – some websites may try to make use of it, but even if you did install it I would recommend explicitly denying it to be used on websites.

  Does Chrome use Java?

  Newer Chrome versions don’t support Java, so you’ll need a plug-in. Enable Java by installing the IE Tab Chrome extension and following the on-screen instructions. Or, install the CheerpJ Applet Runner Chrome extension to run Java applets from within Chrome.

  Do I need Java on my PC?

  At one time, Java was absolutely necessary if you wanted to be able to use your computer for, well, just about everything. Today there is less need for it. A growing number of security experts recommend not installing Java if you don’t already have it, and perhaps even getting rid of it if you do.

  What is full form of Java?

  Java does not have any full form, but a programming language originally developed by James Gosling at Sun Microsystems in 1995. The developers of Java were drinking coffee while they were deciding the name of their programming language. So, they gave it the name “Java” as a slang of “Coffee”. … JAVA means Coffee..

  Is Java a operating system?

  JavaOS is predominantly a U/SIM-Card operating system based on a Java virtual machine and running applications on behalf of operators and security services. Unlike Windows, macOS, Unix, or Unix-like systems which are primarily written in the C programming language, JavaOS is primarily written in Java. …

  Why Java is a technology?

  Java is a technology consisting of both a programming language and a software platform. … Java bytecode runs without modification on any system that supports JVMs, allowing your Java code to be run anywhere. The Java software platform consists of the JVM, the Java API, and a complete development environment.

  From the author

  Greetings! I present my blog about web programming languages. In this blog, I post my notes on the topic of web development languages. I am not a professional programmer, and therefore I do not always have the correct idea of what I am writing. But in most cases, I try to follow the principles of material selection that I have developed over many years of practice.

  ATTENTION TO RIGHT HOLDERS! All materials are posted on the site strictly for informational and educational purposes! If you believe that the posting of any material infringes your copyright, be sure to contact us through the contact form and your material will be removed!

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