Core Java Introduction

Java is a General Purpose and Object Oriented programming language created by James Gosling from Sun Microsystems in 1991. The first publicly released of Java (Java 1.0) in 1995. Java is Based on "write once, run anywhere" (WORA) Feature, meaning that code that runs on one platform does not need to be recompiled to run on another. Java Programs are compiled to bytecode (.class file) that can run on any Java virtual machine (JVM) regardless of computer architecture.


  • Java is one of the slang terms for coffee
  • Today's six million+ Java developers are one of the largest communities of software developers.
  • Java software runs on more types of consumer and embedded devices, smart cards, ATMs, thin clients, PCs, servers, and mainframes than any other software.
  • The Java economy includes 2.5 billion+ smart cards, 800 million+ PCs shipped with Java, 1.85+ billion Java Powered phones , and over 180+ telecom providers who deploy Java technology based content/services.

Features of JAVA

Java is one of the most popular language in the field of software programming. Because of its large number of important and robust features it is widely accepted in software programming.


Simple & Powerful
  • Java is Easy to write and more readable and eye catching.
  • Java has a concise, cohesive set of features that makes it easy to learn and use.
  • Most of the concepts are drawn from C++ thus making Java learning simpler.
Object-oriented
  • Java programming is object-oriented programming language.
  • Like C++ java provides most of the object oriented features.
  • Java is not pure OOP Language (while C++ is semi object oriented)
Robust and Secure
  • Java encourages error-free programming by being strictly typed and performing run-time checks.
  • Java program cannot harm other system thus making it secure.
  • Java provides a secure means of creating Internet applications.
  • Java provides secure way to access web applications.
Platform Independent
  • Platform=hardware+Operating System
  • Java is platform independent so java program can run on any operating system and any hardware configuration.
  • It is because of the magic of Byte Code which is platform indepedent.
  • When java compiler compile any code then it generate the byte code not the machine native code. This byte code need a JRE to execute on a machine.
  • JRE contains JVM and JVM read that byte code and execute it. Different JVM is designed for different OS and byte code is able to run on different OS.
Multithreaded
  • Java supports programming, which allows the user to write programs that perform many functions simultaneously.
  • The two or more part of the program can run concurrently then each part of such a program is called a Thread and this type of programming is called multithreaded programming.
  • Each thread defines a separate path of execution. Thus, multithreading is a specialized form of multitasking.
Interpreted
  • Java supports cross-platform code through the use of Java bytecode.
  • Bytecode can be interpreted on any platform by JVM.
Dynamic
  • Java programs carry with them substantial amounts of run-time type information that is used to verify and resolve accesses to objects at run time.
High performance
  • Bytecodes are highly optimized.
  • JVM can executed them much faster .