java adalah

Java is an object-oriented high-level programming language and a java program composed of parts called classes. The class consists of methods that do the job and return information after performing its task. Many Java programmers take advantage of class sets in the Java class library, called Java Application Programming Interface (API). These classes are organized into groups called packets. The Java API has provided sufficient functionality to create powerful applets and applications. So there are two things to learn in Java, which is learning Java language and how to use classes in the Java API. Classroom is the only way to declare part of program execution, there is no other way. In the Java javac program to compile Java source code files into bytecode classes. The source code file has a .java extension. The javac compiler generates a class bytecode file with a .class extension. Interpreter is the main module of Java system that used Java application and run Java bytecode program.Some advantages java java is a simple language. Java is designed to be easy to learn and use effectively. Java does not provide the complicated features of high-level programming languages, as well as much of the initial programming work that has to be done manually, now being replaced by Java automatically like memory allocation. For programmers who are familiar with C ++ language will quickly learn the structure of Java language but must be alert because Java may take a different direction (semantiks) than C ++.Java is an object-oriented language (OOP) that is a powerful way of organizing and developing software. In OOP, the computer program as a group of interacting objects. OOP short description is to organize the program as a collection of components, called objects. These objects exist independently, have rules communicating with other objects and to command other objects to request certain information or to request another object to do something. Classroom acts as both module and type. As a type then at the time of the path, the program creates objects that are instant-instan classes. Classes can inherit another class. Java does not allow plural inheritance but completes the need for multiple inheritance with a more elegant interface.All programmed objects must be declared first before use. This is the advantage of Java that is Statically Typed. This enforcement allows the Java compiler to define and report the occurrence of incompatibility (type incompatible) which is the initial barricade to prevent unnecessary errors (such as subtracting variables of type integer with string type variables). Prevention as early as possible is expected to result in a clean program. Another good feature of this feature is more program code can be optimized to produce high-performance programs.Java uses a three-layer security model to protect the system from untrusted Java code. First, the bytecode verifier reads bytecode before it runs and ensures bytecode meets the basic rules of Java language. Second, the class loader handles loading Java classes into the runtime interpreter. Third, the security manager handles application-level security by controlling whether the program is entitled to access resources such as file systems, network ports, external processes and window systems.Platform independence is the ability of programs to work on different operating systems. Java language is a language that is perfectly platform independent. Java variable types have the same size across all platforms so that the integer type variables are the same size no matter where the java program is compiled. Once a .class file has been created using a Java compiler on any platform, the .class file can run on any platform. So "wherever it is made, wherever it can be executed". This slogan is commonly summarized as Write Once, Run Anywhere (WORA).Java includes Multithreading languages. The thread is to declare a computer program doing more than one task at a time. Java provides classes for writing multithreaded programs, programs have more than one thread execution at the same time allowing the program to handle multiple tasks concurrently.Java programs do garbage collection which means the program does not need to delete the objects themselves are not used anymore. This facility reduces the memory management burden by programmers and reduces or eliminates the largest source of errors that exist in languages ​​that allow dynamic allocation.Java has a powerful exception-handling mechanism. Exception-handling provides a way to separate the error handling section from normal part of the code so that it leads to a cleaner program code structure and makes the application more robust. When serious errors are found, Java programs create an exception. Exception can be captured and managed programs without the risk of making the system down.The Java program supports the native method of functionality written in another language, usually C / C ++. Native method support allows programmers to write executable functions faster than equivalent functions in java. The native method will dynamically link to the java program, which is associated with the current program.Besides the advantages of using Java programming language among othersthe memory in Java automatically includes a garbage collector that functions to redirect unnecessary memory. No more attempts by programmers to do a dispose (). We are no longer burdened with memory corruption. Java implements the actual array, eliminating the need for malicious pointer arithmetic and easily becomes wrong. Eliminating multiple inheritance is replaced by the interface. And easy to run in various platforms.The graphical user interface (GUI) is one of the Java capabilities in support and graphical interface management. Graphical display to be displayed connected with the program as well as data storage. The basic elements in Java for graphical display creation are two packages, AWT and Swing. Abstract Windowing Toolkit (AWT), also called "Another Windowing Toolkit", is a general-purpose and multiplatform windowing library and provides a number of classes for creating GUIs in Java. With AWT, it can create windows, drawing, image manipulation, and components like Button, Scrollbar, Checkbox, TextField, and pull-down menus.The use of the AWT component is indicated by the instruction: import java.awt. *; Swing is an improvement in weakness in AWT. Many swing classes provide an alternative component to AWT. For example the JButton swing class provides more functionality than the Button class. In addition swing components generally begin with the letter "J", such as JButton, JTextField, JFrame, JLabel, JTextArea, JPanel, and so on. Swing technology uses and expands the AWT ideas. Meanwhile, the use of the Swing component is indicated by the instruction: import javax.swing. *;.Some differences AWT and Swing, AWT is a heavyweight component (heavyweight) while Swing lightweight (lightweight grade). Swing has more components. Swing Look and Feel Facility: Metal, Windows, Motif. The Swing component is model-view, which is a way of developing components with the separation of data storage and handling from the visual representation of data.Java programming language is one of the common programming languages ​​used to develop database applications created using MySQL