Java technology is both a programming language and platform. As a high level language, it is characterized by following buzzwords --- Simple Object oriented Dist Multithreaded Dynamic Architecture neutral Portable High performance Robust, Secure Meaning of these words are explained in “The Java Language Environment” , a white paper written by James Gosling.

The same .class file, also called “bytecode” capable to run on any machine or OS, thru JVM (). Its syntax structure is similar to some extent to C and C++.

As a Plateform – Any hardware or software environment in which a program runs, is known as a platform. Some of the popular platforms are windows, linux, mac. Most platforms can be described as a combination of the operating system and underlying hardware. The Java platform differs from most other platforms in that it's a software-only platform that runs on top of other hardware-based platforms.

Java Platform has two components – JVM and API. The API – is a large collection of ready-made software components that provide many useful capabilities. It is grouped into libraries of related classes and interfaces; these libraries are known as packages.

As a platform-independent environment, the Java platform can be a bit slower than native code. However, advances in and virtual machine technologies are bringing performance close to that of native code without threatening portability.

The terms"Java Virtual Machine" and "JVM" mean a Virtual Machine for the Java platform.

Copmonents of Java -

 Development Tools: The development tools provide everything needed for compiling, running, monitoring, debugging, and documenting user applications. As a new developer, the main tools you'll be using are the javac compiler, the java launcher, and the javadoc documentation tool.

 Application Programming Interface (API): The API provides the core functionality of the Java programming language. It offers a wide array of useful classes ready for use in your own applications. It spans everything from basic objects, to networking and security, to XML generation and database access, and more. The core API is very large; to get an overview of what it contains, consult the Java Platform Standard Edition 8 Documentation.

 Deployment Technologies: The JDK software provides standard mechanisms such as the software - Servelet and Java Plug-In software for deploying your applications to end users.

 User Interface Toolkits: The JavaFX, Swing, and Java 2D toolkits make it possible to create sophisticated Graphical User Interfaces (GUIs).

 Integration Libraries: Integration libraries such as the Java IDL API, JDBC API, Java Naming and Directory Interface (JNDI) API, Java RMI, and Java Remote Method Invocation over Internet Inter-ORB Protocol Technology (Java RMI-IIOP Technology) enable database access and manipulation of remote objects.

History - Java was developed by James Gosling and his team called – Green Team, at Sun Microsystem in 1991. It was initially called – OAK but later renamed as “Java” in `995. Earlier it was developed by consumer electronic items – program but later becomes popular for internet applications. Its systax is similar to C / C++. It is an Object Oriented Programming language. Its plateform independent nature make it unique. It implements on internet as java Applets (old concept now taged as obselete), Servelet – Server side programming.

SDKs (Software development Kit) and Tools - Java Editon Used for …. Latest Release as on 1 May. SE - Standard ed. Desktop applications and GUI Ver – 12.0.1 forms EE - Enterprise ed. Enterprise applications use Ver - 8 database, server – Glassfish or Apache Tomket ME - Micro ed. Embeded and mobile devices Ver - 8

Conclusion - Since the beginning it has redefined programming for internet. The bytecode and JVM changed the way about thinking of security and portability. Every six month it produce a new release.