What is Java Programming
Java is an object oriented programming language, which is used for developing complex software and web applications. Nowadays, Java is one of the most popular choices of programmers to develop mobile applications.
Java first released by Sun Microsystems in 1995 and at present owned by Oracle. So, you can download Java from the Oracle website.
What is Java Program
Java program is mainly based on Class definition and a main method. You can't write a Java program without main method and class. It also consists of various objects and methods that communicate by invoking each others properties.
In a Java class you can write and invoke any number of objects with in the same class or outside a class using inheritance and other features provided by Java.
A Java program is always saved as 'classname.java'. '.java' is the extension of a Java class.
What is required for Java programming
To write and run a Java application you must have the following software installed on your computer.
Java Virtual Machine (JVM) or Java Runtime Environment (JRE).
Java Virtual Machine process and converts your code into bytecode and coverts it in to the class file. That is why JVM is required to run the Java application.
You can download your JVM from the Oracle website. Here is the link.
You can find the JVM manual here
Java Software Development Kit (SDK) is required to write and test the Java codes. You can download the Software Development kit from the Oracle website.
Java Integrated development environment (IDE) is integrated software that comes with in-built set of tools and libraries to facilitate the developers. It also consists of source code editors, automation tools and debugger. Net Beans and Eclipse are few examples of Java IDE.