Java Introduction

The main points from this module are:

• Java is a programming language and computing platform first released by Sun Microsystems in 2995. Created by a team led by James Gosling. The language was first named Oak, after the tree outside James' window. 
• Java software runs on everything from laptops to data centers, game consoles to scientific supercomputers. 
• The Java Runtime Environment (JRE) contains the parts of the Java SE platform required to run Java programs is intended for end-users.
• The Java Development Kit (JDK) intended for software developers includes development tools such as the Java compiler, Javadoc, Jar, and a debugger.
• Java 'System.out.println()' is used to print an argument that is passed to it.
• The order required to process a Java programing is source->Bytecode->JVM->Operating System->Hardware.
• To set up the developer environment for Java we have to install a JDK (Java Development Kit).
• Syntax defines the rules for writing code using a specific programming language. Java syntax is very similar to C++, C, C#, etc. Like these other programming languages, Java marks the end of a statement with a ; (semicolon). 
• Extra spaces and lines referred to as whitespace in your code are ignored by Java.
•  A variable is nothing more than a named storage location in memory for a specific data type.
• Operators act upon variables, objects and literals in an order specified by Java.
• Javadoc is a tool that comes with JDK and it is used for generating Java code documentation in HTML format from Java source code.
• Controlling the flow of execution allows us to execute a set of Java statements if a certain condition is TRUE. 
• A loop allows us to repeat a collection of code statements some number of times refers to as iteration.
• An array can store a group of values, but the values must be of the same data type.
• Everything in Java is an object. 
• Inheritance provides the ability to extend the capabilities of an existing class.
• Every object is a subclass of the Java Object class. 
• NetBeans environment in Java can be used to add a class.
• The run() method of thread class is called if the thread was constructed using a separate runnable object otherwise this method does nothing and returns.
• 'this' keyword in Java is a reference variable that refers to the current object.
•  Inheritance provides the ability to extend the capabilities of an existing class.
• The get() method in Java returns the variable value.
• An interface defines a set of commands that a class will implement.