Java

Java technology's versatility, efficiency, platform portability, and security make it the ideal technology for network computing. From laptops to datacenters, game consoles to scientific supercomputers, cell phones to the Internet, Java is everywhere!
We consider several important questions:

• Why is Java the leading technology today?
• Why are Java skills in greater demand than skills with any other programming platform/language?
• How do Java's future prospects look?

Why is Java in such high demand?

Here are some of the reasons why Java is so popular today.
Java is simple. That simplicity derives from syntax similar to C/C++ and the omission of complex C/C++ features such as multiple implementation inheritance, pointers, and operator overloading.

• Java is object-oriented. Java’s object-oriented nature encourages a developer to think in terms of classes and objects rather than separate code and data. That class/object focus results in code that is easier to write, easier to maintain, and easier to reuse.
• Java is network-savvy. A TCP/IP library simplifies the development of programs that communicate with HTTP, FTP, and other TCP/IP network processes. Furthermore, the library’s use of the same stream-oriented mechanism for communicating with remote network processes that file-oriented code uses to communicate with files on a computer’s local hard drive helps a developer write network code faster.
• Java is interpreted. Java’s compiler translates source code into class files of bytecode instructions. A virtual machine examines each instruction and uses that instruction’s meaning to execute an equivalent sequence of platform-dependent instructions. Interpretation speeds up the development process and simplifies debugging.
• Java is robust. Errant programs do not crash the virtual machine or corrupt the underlying (native) platform. Robustness is achieved, in part, by not supporting C/C++ pointers, by providing a garbage collector to automatically free up dynamically allocated memory (instead of forcing the developer to accomplish that task), by performing strict compile-time/runtime type checking, and by providing true arrays with bounds checking.
• Java is secure. Java’s "sandbox" security model identifies sensitive operations (such as file I/O) that a malicious program can exploit to harm the native platform, and provides a mechanism for allowing or preventing access to those operations.
• Java is architecture-neutral. A compiled Java program’s bytecode instructions target a generic virtual machine instead of a specific platform. Because each platform-specific virtual machine implementation supplies a consistent interface to the byte codes, the same Java program runs on diverse platforms (via their virtual machines).
• Java is portable. Portability is achieved through architecture neutrality and through a strict definition of the language (which permits no implementation-dependent features). For example, Java’s integer primitive type always means a signed 2’s complement 32-bit integer. In contrast, the C/C++ integer type can be unsigned, and its size varies according to a platform’s register size (typically 32 bits or 64 bits).
• Java is high-performance. Many virtual machines use a just-in-time (JIT) compiler to dynamically compile a program’s bytecode instructions into platform-specific instructions (which execute faster than byte codes) as the program runs.
• Java is multithreaded. Support for threads is built into the language via thread-synchronization primitives. There is also a thread library.
• Java is dynamic. Java’s use of an interface type to distinguish between what a programs must do and how that task gets accomplished helps Java adapt to a continually evolving environment, and makes it easier for vendors to modify Java libraries without breaking program code that uses those libraries.

The above definition implies that Java is not your average computer language. Unlike many computer languages, a Java compiler doesn’t translate correct source code (based on a language specification’s syntax and semantics) to equivalent executable code that runs directly on Microsoft Windows/Intel, Sun Solaris/SPARC, or another platform (an operating system and hardware architecture combination). Instead, Java’s compiler translates correct source code to executable code that runs indirectly on a native platform via a virtual machine (a software representation of a hypothetical computer). The virtual machine presents a well-defined interface to a Java program’s bytecode instructions (operation codes and operands that have meaning to the virtual machine) and situates between a Java program’s byte codes and the native platform.
Initially these goals were ambitious and required developers to spend a significant amount of time testing and debugging their applications running in different virtual machines on different operating systems, but as time moved forward, so did Java. Today, moving between modern Java virtual machines, even from different vendors, is mostly transparent. No longer do you have to think about if your application will run on Linux or Windows, if you choose to use Java you get both for free, plus Macintosh, Sun, AIX, HP-UX, and any other operating system for which there is a Java virtual machine.