Java Login

About javalogin.com

Hello guys,
javalogin.com is for Java and J2EE developers, all examples are simple and easy to understand 

It is developed and maintained by Vaibhav Sharma. The views expressed on this website are his own and do not necessarily reflect the views of his former, current or future employers. I am professional Web development. I work for an IT company as Senior Consultant. Primary I write about spring, hibernate and web-services. I am trying to present here new technologies.

Java is not to be confused with JavaScript, it has been built as a Write once, run anywhere language - which in simple technical terms means that it can be run on pretty much any device that there is.
JAVA was developed by Sun Microsystems Inc in 1991, later acquired by Oracle Corporation. It was developed by James Gosling and Patrick Naughton. It is a simple programming language. Writing, compiling and debugging a program is easy in java. It helps to create modular programs and reusable code.


What is Java Programming Language?

Java is awesome language and if you are a developer than you must familiar with it. Java is object oriented programming language and currently used by all over world in billions of applications. If you are beginner in Java and searching for resources to learn java than this post will help you. Here I am going to list few really nice resource from where you can learn Java.


Features of Java Language

Java is a simple, robust and secure programming language. Here are the key features of Java:

  • Simple: The Java language is easy to learn. Java code is easy to read and write.
  • Object-orientated programming language: Except the primitive data types, all elements in Java are objects.
  • Familiar: Java is similar to C/C++ but it removes the drawbacks and complexities of C/C++ like pointers and multiple inheritances. So if you have background in C/C++, you will find Java familiar and easy to learn.

Java Virtual Machine (JVM)

This is generally referred as JVM. Before, we discuss about JVM lets see the phases of program execution. Phases are as follows: we write the program, then we compile the program and at last we run the program.
1) Writing of the program is of course done by java programmer like you and me.
2) Compilation of program is done by javac compiler, javac is the primary java compiler included in java development kit (JDK). It takes java program as input and generates java bytecode as output.
3) In third phase, JVM executes the bytecode generated by compiler. This is called program run phase.

So, now that we understood that the primary function of JVM is to execute the bytecode produced by compiler. Each operating system has different JVM, however the output they produce after execution of bytecode is same across all operating systems. That is why we call java as platform independent language.


Java Development Kit(JDK)


While explaining JVM and bytecode, I have used the term JDK. Let's discuss about it. As the name suggests this is complete java development kit that includes JRE (Java Runtime Environment), compilers and various tools like JavaDoc, Java debugger etc.
In order to create, compile and run Java program you would need JDK installed on your computer.

Java Runtime Environment(JRE)


JRE is a part of JDK which means that JDK includes JRE. When you have JRE installed on your system, you can run a java program however you won't be able to compile it. JRE includes JVM, browser plugins and applets support. When you only need to run a java program on your computer, you would only need JRE.