Saturday, October 24, 2009

Program java, API, JVM, OOP, GUI

Java is a programming language using the term or machine code interpreter in java programs that can run on different computers, including mobile phones. Platform is a hardware or software environment in which a program can run in it. Example platform is Microsoft Windows, Linux, Solaris OS and Mac OS. A platform is usually a combination of operating system and a set of hardware. Java terminology not only referring to a language program. But also as a platform. But the Java platform consists of software components (without any hardware component).
Language Programs
As a programming language, java has a syntax (in human language is the vocabulary, Grammar and sentence) is similar to the language C. Machine paradigm is Object Oriented Programing (OOP) or object-oriented programs. The emphasis is not on the line (structure) but the object, property and state-state owned by the object. Here Java is present to overcome the constraints (complexity) predecessor and eliminates the language barriers between the operating system. Java has a very popular jargon that is write once run anywhere is abbreviated by Wora.
As a Virtual Machine
Java Virtual Machine (JVM) is a machine that interprets bytecode virtaul-java bytecode into machine language. Java bytecode file is a compilation of java code (the file extension is. Class). If a java program called compiled the result is ProgramA.class (this is called bytecode java). Actually the program machine paradigm in a way to Interpret the code (in java is the bytecode) according to experts is less good than the performance (speed). But JVM tries to overcome this problem by applying the techniques just in time (JIT) compilation of java bytecodes directly compiled into machine language for the program code is executed repeatedly.

Application Programming Interface (API) is a collection of software components (classes and interfaces java) ready for use with various uses and capabilities different. A set of classes and interfaces related organized in a library. This library is called the package (package).

excess using java program :
  1. Automatic garbage collection, has a facility setting memory usage so that the programmers do not need to do direct memory settings (such as in C + + language is widely used).
  2. such as C + + programs, a programming language syntax such as [C + +] that attract a lot of C + + programmers moving to Java. We have so many Java users, mostly C + + programmer who moved to Java. Universities in the United States also began to move to teach Java to students who just because they are more easily understood by students and can be useful also for those who are not majoring in computer.
  3. OOP (Object Oriented Programing) which means that all aspects contained in Java is Object. Java is a programming language is purely object-based. All types of data derived from the basic class called Object. It is very easy for programmers to design, create, develop and allocate fault to the base of a Java program is faster, precise, easy and organized. This excess makes Java as one of the easiest programming language, even for the advanced functions such as communications between computers though.
  4. Multiplatform. The principal advantage of Java is to be run on multiple platforms / operating system, in accordance with the principle write once, run everywhere. With these advantages enough programmer to write a Java program and compile (modified, from the understandable human language into machine language / bytecode) once and then the results can be run on multiple platforms without changes. This excess allows a java-based programs work on Linux operating system but it runs well on Microsoft Windows. Supported platforms so far are Microsoft Windows, Linux, Mac OS and Sun Solaris. The reason is that each operating system uses its own program (which can be downloaded from the Java site) to interpret the bytecode.
Lack of java programs :
  1. The main problem in netbeans platform is he controlling class loader with the mechanism itself, so if we work with Spring, hibernate, jpa will arise a fairly complicated issue and need a little hack.
  2. Easy to compile. compilation is the reverse process of the code so the source code. This is possible because the code is a Java bytecode that stores many attributes of high-level language, such as class names, methods, and data types. The same thing happened to Microsoft. NET Platform. Thus, the algorithm used to program more difficult to hide and easily hijacked / direverse-enginer.
  3.  There are still some things that are not compatible between the platforms of the other platforms. For J2SE, for example SWT-AWT bridge that until now does not work on Mac OS X.
Phase Compiling Java :
  1. Write / Modify. Programmers to write programs and store it in the media in the form of file '. Java'.
  2. compile the bytecodes of the program to form a shape file '. class'
  3. consists of bytecodes to load classes into memory.
  4. verification ensures bytecodes do not interfere with the security system of Java.
  5. translates bytecodes into machine language. 
Developed by Sun Microsystems and published in 1995.
java.lang: Appropriation class basic elements. Appropriation input and output classes, including the use of the file.
java.util: Appropriation supplementary classes, including classes and data structures class calendar class. The Appropriation class TCP / IP, which enables to communicate with other computers using TCP / IP network.
java.awt: base class for applications with a user interface GUI (Graphical User Interface).
java.applet: base class interface application to apply to a web browser.

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