Java Overview
Java is a programming language that is object oriented. It was created in the 1990s by James Gosling, who worked with Sun Microsystems. While most programming languages are designed to be compiled in to basic code, Java is designed to be compiled to bytecode.
This bytecode can then be processed by the Java Virtual Machine. A lot of the code that Java uses is taken from programming languages such as C++. However, Java uses an approach which is much more simple than C++ or C.
The creators of Java have five important philosophical goals for the language. Java is a language which should be easy to use, and it should also be able to borrow important elements from older programming languages. It should always use an object oriented approach. Any programs which are created in Java should be able to run on multiple operating systems, and should never be limited to a single OS. It should also be designed to work with computer networks, and it should also be able to remotely initiate code. These are the five goals of Java.
As of this writing, seven versions of Java have been released or are in development. The latest is Java SE 7, which is also known as dolphin. It is set to be released in 2008. To understand Java, it is first important to understand object oriented programming. This is a method of programming and design which allows the various forms of data which have similar operations to be combined together. For example, data and code will be combined in what is called an "object." An object is a type of package which contains the state and behavior. The behavior is the code, and the state is the data. The goal of object oriented programs like Java is to separate things which alternate from things that remain static. It has been shown that this method of programming makes a language more stable, and it is also easier to work with.
The ability for applications written in Java to run on multiple platforms is extremely important. The creators of Java felt that an application should be able to run on multiple pieces of hardware once it is created. The Java compiler is responsible for this feature. It will compile the Java code into bytecode. Bytecode is basic machine instructions which can be used on the virtual machine. The virtual machine is a program written in relative code for hardware which will study and use the Java bytecode. A library will often be used to give entrance to elements of the host device. These elements could include networking or graphics. The JIT compiler is responsible for transforming the Java bytecode into a code which is understood by the device.
Another feature that Java has is called the automatic garbage collection system. With older languages such as C++, programmers are required to manually deal with memory. If the programmer fails to deal with memory, the program may consume too much memory. This is called a memory leak, and can cause the program to crash. Java solves this problem by using the garbage collector. The Java runtime will manage the lifespan of objects. If there are no references to a specific object, the garbage collector will delete it. It will do this in order to make room for memory and avoid memory leaks. This feature makes the design and deletion of objects easier than C++.
While the syntax used with Java is based on C++, there are a number of differences. Java is a true object oriented programming language. Virtually everything within the Java system will be an object, and it will all be written within a class. All programs created in Java will be written within a class, even programs thate are designed to be standalone applications. The file name for programs written in Java will always use the .java suffix. The compiler will also create a class file for every class that is registered in the source file. Java is a very impressive program which has a large number of useful applications. However, it has become the target of crticism since it was created.
Java is not a language which works for all programmers. Many considered the earlier versions of the language to be a lot slower and memory intensive than C++. However, this has changed considerably with newer versions of the language.
