Java (programming language)

Java logo.

Java is an object-oriented programming language developed by Sun Microsystems in the 1990's. Its syntax is similar to that of C++, but with some modifications. One of the major features which make Java programs easier to write than C++ programs is its support for automatic memory management.

• Java managed to cover two problems plaguing the C/C++ world: complexity (C++) and memory management (C/C++). These two were real problems because projects plagued with bugs created by complexity and with memory leaks. [1]

The Java compiler provided by Sun Microsystems compiles Java code to bytecode, which requires the Java Virtual Machine (commonly referred to as a JVM) to execute. This model was adopted by Microsoft for C# and other .NET languages. IBM and others supply regular Java compilers for those who don't want to use the virtual machine.

Java applications are popular in creating applets for websites, due to their cross-platform nature. It still has not gained widespread popularity in stand-alone Windows applications, but is used primarily on web servers.

Google's Dalvik, based on Java, is a programming language used on Android. Oracle (who acquired Sun Microsystems in 2009) has filed a lawsuit alleging that Dalvik infringes Oracle's copyrights and patents on the Java programming language. The lawsuit is currently being tried, as of April 2012.

Memory Management

The Java programming language is based on Object Oriented programming principles, coupled with garbage collection. This means, unlike C and other lower level programming languages the developer is able to create programs without worrying about pointers, references and memory. Instead the Java Virtual Machine is able to manage objects that are in use, periodically deleting objects that are no longer referenced (and therefore no longer required by the program). This memory management system, as well as memory management systems in general, make programs that require dynamic memory allocation much more convenient to write. The tradeoff of this is that performance of the program will generally decrease, which is why languages like C and C++ are used in applications that require high performance, such as video games.

Example Code

Hello, World

An example program often used for languages is something that displays "Hello, World!".

public class World
{
    public static void main(String[] args) 
    { 
        System.out.println("Hello, World!"); 
    }
}

GUI with JFrame

An example of creating and showing a JFrame with nothing in it:

JFrame frame = new JFrame();
frame.show();

External Links

Official Java Website