What is Java and why need to choose it, installed..JDK, JRE

What is Java and why need to choose:

Java is a programming language to develop the standalone application, web based, enterprise applications. Every Java developer needs obviously to be installed in their system for their needs.

As well, who does not develop Java applications and hate Java also need to install at least JRE because some of the software's are developed in Java. So to execute or run applications Java runtime environment is required.

Java is free to download and free license. Java available in 30+ languages.

When we download JDK and install it. Than we get development tools and JRE. JRE means Java Runtime Environment which consists of Java Virtual Machine(JVM), core classes along with the required core libraries. We can understand that JRE is a part of Java installation. Or individually we can install only JRE. Java plugin is required to run web browser.

1) Java follow syntaxes of similar to C++ but OOPS concepts are shaped after modelled Smalltalk and Objective-C. Java has integrated with automatic garbage collection.

2) In Java language, we write java code and save file with extension of .java. After saving the Java program, we have to compile(JDK has internally compiler. We no need to do external). After compilation, .class file will be generated.

3)  We already specified that "Write Once, Run Anywhere" which means write program on one platform and run on any other platforms. Because Java generates .class file which is in the format of Byte Code. Byte Code is platform independent. This Byte Code can be executed by Java Virtual Machine(JVM) on any platform. After writing several .java files than have to generated compiled version of .class files, put in jar file or library.

4) JVM has been implemented for different operating systems. But, once .class files are generated we can run these .class files on any operating systems(OS) windows, unix, Mac OS, etc..

5) Java has good environment to handle threading mechanism and sufficient memory model.

6) Java has high performance and vendor independent executable binaries.