Introduction to Java
Developed by Sun Microsystems INC in 1991 and later acquired by Oracle Corporation. Developers: James Gosling and Patrick Naughton. Java is highly used for software development and more because it is simple to write as it supports HLL- High-Level Language and early checking of lots of possible errors. Moreover, it helps us to work in a team by creating modules of our software. Many devices can execute Java programs directly. If you want to learn java then you should know why Java is used and be familiar with its terminology
Platform independent – is portable
Simple, because it excludes operator overloading, Multiple Inheritance, pointers and explicit memory allocation
Early Checking of possible errors which unlikely to be in other programming languages
Secure – because there are no pointers and is a robust language(checks errors previously)
JVM – Java Virtual Machine
JDK – Java Development Kit
JRE – Java Runtime Environment
Well, Programmers like you and us write Java programs, then JDK compiles our program and gives bytecodes as output. Further, JVM executes the output of bytecode to give the real output of the program. So, it is important to install JDK first to start our java program.
JRE is a subset of JDK i.e. JDK includes JRE installed on a system which can run the java program but will be unable to compile it. And hence, you can only install JRE if you are non-programmers or don’t want to compile and debug the program.
An applet is a program in Java(TM) programming language to run within a web browser. Applets are compatible with the Java platform, such as HotJava (TM) or Netscape Navigator(TM).
Abstract Window Toolkit (AWT)
A collection of graphical user interface (GUI) components that were implemented using native-platform versions of the components. These components provide that subset of functionality which is common to all native platforms. Largely supplanted by the Project Swing component set. Frame, Buttons, TextField are some inbuilt components of AWT.
A collection of graphical user interface (GUI) components that run uniformly on any native platform which supports the Java(TM) virtual machine. Because they are written entirely in the Java programming language, these components may provide functionality above and beyond that provided by native-platform equivalents. (Contrast with AWT.) We can just add capital alphabet J as a prefix to AWT to use swing set. For example JFrame, JButtons, JTextField etc.
Technology Compatibility Kit (TCK)
A test suite, a set of tools, and other requirements used to certify an implementation of a particular Sun technology conformant both to the applicable specifications and to Sun or Sun-designated reference implementations.