Java is a proprietary language developed by Sun Microsystems. Originally intended as a programming language suitable for supporting an environment of networked machines and embedded systems. Java did not really fulfill its potential until the internet and the web started to become popular. Now, Java is rapidly becoming the de facto standard programming language for Web computing.
The importance of the Java language and its related technologies has been increasing for the last few years. Java is a type-safe, object oriented programming language that is interesting because of its potential for building Web applications (applets) and server applications (servlets) (Gosling et al.,2000). with the widespread interest in Java, its similarity to 'C' and 'C++', and its industrial support, many organizations are making Java their preferred language. Java is 'a simple, object-oriented, distributed, interpreted, robust, secure, architecture neutral, portable, high-performance, multi-threaded and dynamic language' (Sun 1997).
Java Architecture
Java is particularly interesting because of its machine-independent target architecture, the Java Virtual Machine (JVM) (Arnold et al.,2000). for this reason, Java is often quoted as a 'write once run anywhere' language. The Java environment is shown in figure :
The Java compiler takes a '.java' file and generates a '.class' file, which contains bytecode instructions that are independent of any particular computer architecture. These bytecodes are both easy to interpret on any platform and are easily translated into native methods. The JVM can interpret and execute Java bytecodes directly on any platform to which an interpreter and runtime system have been ported. Since almost every Web browser vendor has already licensed Java and implemented an embedded JVM. Java applications can currently be deployed on most end-user platforms.
Before a Java application can be executed, it must first be loaded into memory. This is done by the class loader, which takes the '.class' files containing the bytecodes and transfers it into memory. The class file can be loaded from the local hard drive or it can be downloaded from a network. Finally, the bytecodes must be verified to ensure that they are valid and that they do not violate Java's security restrictions.
Loosely speaking Java is a 'safe' C++. Its safety features include strong static type checking, the use of implicit storage management through automatic garbage collection to manage deallocation of dynamically allocated storage, and the absence of machine pointers at the language level. These features combine to make Java free of the types of pointer misuse that are the cause of many errors in C/C++ programs. These Safety transmit Java code across the internet. Security is also an integral part of Java's design. It has been described using the metaphor of the Sandbox. The Sandbox ensures that an untrusted. Possibly malicious, application cannot gain access to system resources.
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The importance of the Java language and its related technologies has been increasing for the last few years. Java is a type-safe, object oriented programming language that is interesting because of its potential for building Web applications (applets) and server applications (servlets) (Gosling et al.,2000). with the widespread interest in Java, its similarity to 'C' and 'C++', and its industrial support, many organizations are making Java their preferred language. Java is 'a simple, object-oriented, distributed, interpreted, robust, secure, architecture neutral, portable, high-performance, multi-threaded and dynamic language' (Sun 1997).
Java Architecture
Java is particularly interesting because of its machine-independent target architecture, the Java Virtual Machine (JVM) (Arnold et al.,2000). for this reason, Java is often quoted as a 'write once run anywhere' language. The Java environment is shown in figure :
The Java compiler takes a '.java' file and generates a '.class' file, which contains bytecode instructions that are independent of any particular computer architecture. These bytecodes are both easy to interpret on any platform and are easily translated into native methods. The JVM can interpret and execute Java bytecodes directly on any platform to which an interpreter and runtime system have been ported. Since almost every Web browser vendor has already licensed Java and implemented an embedded JVM. Java applications can currently be deployed on most end-user platforms.
Before a Java application can be executed, it must first be loaded into memory. This is done by the class loader, which takes the '.class' files containing the bytecodes and transfers it into memory. The class file can be loaded from the local hard drive or it can be downloaded from a network. Finally, the bytecodes must be verified to ensure that they are valid and that they do not violate Java's security restrictions.
Loosely speaking Java is a 'safe' C++. Its safety features include strong static type checking, the use of implicit storage management through automatic garbage collection to manage deallocation of dynamically allocated storage, and the absence of machine pointers at the language level. These features combine to make Java free of the types of pointer misuse that are the cause of many errors in C/C++ programs. These Safety transmit Java code across the internet. Security is also an integral part of Java's design. It has been described using the metaphor of the Sandbox. The Sandbox ensures that an untrusted. Possibly malicious, application cannot gain access to system resources.
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