JAVA WORLD: JAVA BUZZWORDS/FEATURES

Since Java is an object oriented programming language it has following features:

Re-usability of Code
Emphasis on data rather than procedure
Data is hidden and cannot be accessed by external functions
Objects can communicate with each other through functions
New data and functions can be easily added Java has powerful features. The following are some of them:-

Java was designed to be easy for the professional programmer to learn and use effectively. If you already understand the basic concepts of object-oriented programming, learning Java will be even easier. Best of all, if you are an experienced C++ programmer, moving to Java will require very little effort. Because Java inherits the C/C++ syntax and many of the object-oriented features of C++, most programmers have little trouble learning Java.

Although influenced by its predecessors, Java was not designed to be source-code compatible with any other language. This allowed the Java team the freedom to design with a blank slate Borrowing liberally from many seminal object-software environments of the last few decades, Java manages to strike a balance between the purist's “everything is an object” paradigm and the pragmatists “stay out of my way” model. The object model in Java is simple and easy to extend, while simple types, such as integers, are kept as high-performance non-objects.

The multi-platformed environment of the Web places extraordinary demands on a program, because the program must execute reliably in a variety of systems. Thus, the ability to create robust programs was given a high priority in the design of Java. There are two type of handling and in which they are Memory Handling
Java deallocate itself dynamically allocated memory using garbage collector done by JVM
When an error occurs in a Java program it usually results in an exception being thrown. How you throw, catch and handle these exception matters.

Java was designed to meet the real-world requirement of creating interactive, networked programs. To accomplish this, Java supports multi-threaded 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 multiprocess synchronization that enables you to construct smoothly running interactive systems. Java's easy-to-use approach to multi-threading allows you to think about the specific behavior of your program, not the multitasking subsystem.

A central issue for the Java designers was that of code longevity and portability. One of 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, any time, forever.” To a great extent, this goal was accomplished.

As described earlier, Java enables the creation of cross-platform programs by compiling into an intermediate representation called Java byte-code. This code can be interpreted on any system that provides a Java Virtual Machine. Most previous attempts at cross-platform solutions have done so at the expense of performance. Other interpreted systems, such as BASIC, Tcl, and PERL, suffer from almost insurmountable performance deficits.

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 intraaddress- space messaging. This allowed objects on two different computers to execute procedures remotely. Java revived these interfaces in a package called Remote Method Invocation (RMI). This feature brings an unparalleled level of abstraction to client/ server programming.

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 byte-code may be dynamically updated on a running system.