Java Features

1. Multiplatform

In most of programming languages, a program code have to be compiled and interpreted so can be run on a computer. Software used to compile the program code called compiler, while used for interpretation called interpreter.

Java implements the two processes above. This means that Java acts as compiler and also as interpreter. The concept is simple, first, program code written in Java (with .java extension) will be compiled (by compiler) into an object. In Java terminology, this object code is called as bytecode. So, in Java, the end result of program will be a bytecode (with .class extension), instead of the .exe file. Furthermore, the bytecode will be executed line by line (by interpreter). Thus, the compilation process is done only once, but interpretation process will be done every time the program is executed.

Bytecode can be reputed as a set of commands in machine language for a JVM (Java Virtual Machine). Every Java interpreter, whether development tool or a web browser, is implementation of JVM. Program created in Java can not run on a computer or other device that does not have a JVM.

With the bytecode concept, in Java terminology known the term "write once, run anywhere" (WORA). This means that once we write Java program and compile it, then its bytecode can be run in any platform as long as the platform has JVM. For example, the following image shows the same program but can be run on the Windows, Linux, and Mac platform.




2. Object Oriented

Java is Object-Oriented Programming (OOP). OOP modeling the real world into the object and the interaction between these objects. OOP aims to facilitate the program development by following the existing model in everyday life. So every part of the problem is an object, and object itself is a combination of several smaller objects again.

For example is a car. A car is an object. A car itself is made up of several smaller objects like machine, wires, bolts, wheels, brakes, etc. A car as an object formed from the smaller objects that interconnected, interact, communicate and send messages each others. So also with the program, a large object formed from smaller objects that communicate and interact with each others.

Java split the program into objects and modeling the properties and behavior of each in resolving a problem. All aspects contained in Java is object. It is easy for programmers to design, create, and develop a program in a fast, precise, easy and organized. This excess makes Java as a programming language that is easy to use, even for advanced functions such as communication between the computer though.


3. Complete Library

Java has complete library, that is a collection of programs that are included in Java, which greatly facilitate programmers to build applications. Completeness of these libraries coupled with the existence of a large community of Java that continuously create new libraries to cover all application development needs.


4. Multithreading

Multithreading is the ability of a computer program to work on some processes within a time simultaneously/concurrently. This means that, at the same time, we can run more than one process in a program.

For example, suppose we were using a word processor application. At the same time, we can do the formatting of text and once the process of printing the document. This can happen because text formatting process and printing document process are stored in separate thread. In a programming language that does not support multithreading, then both of the work should be done sequentially. That is, in this case, the process of printing the document can not be done before the text formatting process is complete. In other words, both can not be done simultaneously.

Thread in Java have the ability to take advantage of multi-processor if the operating system supports multiple processors.


5. Garbage Collection

Java has a garbage collector facility that works automatically to ensure the availability of memory to free up unused memory.

Many other programming language that allows a programmer to allocate memory at run time. However, after using the memory allocation, there must be a way to put back the memory block so that other programs can use them. In C, C++ and other languages, programmers are responsible for this. It can be difficult when the programmers forgot to return the memory block, causing a situation known as memory leaks.

Java programs do garbage collection which means that programmers do not need to remove their own objects that are not used anymore. This facility reduces the burden of memory management by programmers and reduce or eliminate sources of error that contained in a language that enables dynamic allocation.


6. Exception-Handling

The worst thing and avoided in programming is a bug (error) during the process execution in the program that we have created. In general, these errors are also called exception. According to the general definition, the exception is an abnormal condition that occurs at runtime.

In other programming languages that do not support exception-handling mechanism, errors that occur must be checked manually (usually through a specific error code). Such a way would have a weakness that is difficult in tracking process . To overcome this problem, Java provides an error-handling mechanism called exception-handling. Any errors will be formed into an object.

As a programmer, we have to be able to think of all possibilities of errors in the program and be able to handle it well.

Java has a powerful exception-handling mechanism. Exception-handling provides a way to separate the error handling section with normal code section that leads to the structure of the program code is cleaner and makes the application more rigid. When a serious error is found, the Java program creates exception. Exception can be captured and managed without the risk of making the system to be down.