The features in java

By: aathishankaran Printer Friendly Format

Although the fundamental forces that necessitated the invention of java are portability and security, other factors also played an important role in molding the final form of the language. The key considerations were summed up by the java team in the following list of key words

Multithreaded
Architecture-Neutral
Interpreted and high performance
Distributed
Dynamic

Let examine this key words what each of them implies.

Multithreaded

Java was designed to meet the real-word requirement of creating interactive, networked programs. To accomplish this, java supports multithreaded programming which allows you to write programs that do many things simultaneously. The java run-time system comes with an elegant yet sophisticated solution for multi process synchronization that enables you to construct smoothly running interactive systems. Java’s easy-to-use approach to multithreading allows you think about the specific behavior of your program, not the multitasking subsystem.

Architecture-Neutral

A central issue for the java designers was the java designer was that of code longevity and portability. One or the main problems facing programmers is that no guarantee exists that if you write a program today, it will run tomorrow – even on the same machine. Operating system upgrades, processor upgrades, and changes in core system resources can all combine to make a program malfunction. The java designers made several hard decisions in the java language and the java virtual machine in an attempt to alter this situation. Their goal was “write once; run anywhere, anytime, forever.” To a great extent, this goal was accomplished.

Interpreted and High Performance

As described earlier, java enables the creation of cross-platform programs by compiling into an intermediate representation called java bytecode. This code can be interpreted on any system that provides a Java Virtual Machine. Most previous attempts at cross-platform solution have done so at the expense of performance. Other interpreted systems, such as BASIC, Tcl, and PERL, suffer from almost insurmountable performance deficits. Java, however, was designed to perform well on very low-power CPUs. While it is true that java was engineered for interpretation, the java bytecode was carefully designed so that it would be easy to translate directly into native machine code for very high performance by using a just-in-time compiler. Java run-time systems that provide this feature lose none of the benefits of the platform independent code. “High-performance cross-platform” is no longer an oxymoron.

Distributed

Java is designed for the distributed environment of the Internet, because it handles TCP/IP protocols. In fact, accessing a resource using a URL is not much different from accessing a file. The original version of java (Oak) included features for intra-address-space messaging. This allowed objects on tow different computers to execute procedures remotely. Java has recently revived these interfaces in a package called Remote Method Invocation (RMI). This feature brings an unparalleled level of abstraction to client/server programming.

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. This makes it possible to dynamically link code in a safe and expedient manner. This is crucial to the robustness of the applet environment, in which small fragments of bytecode may be dynamically updated on a running system.