Compiler :A software which converts high level language code in to machine level language(binary code). It complies the instructions at once and lists all the errors.
Interpreter : A software which converts High level language to machine level language line by line .It does not move to next line until the error is corrected.it is slower than compiler.
Source Code : A set of instructions written in high level language (by the programmer), which is taken as an input from the user .
Machine code : The source code which is Complied/Interpreted is known as Machine code .
Byte Code : Byte code is the simplest Form of Source code. Source code is compiled to an intermediate code called Byte code. It can easily pass from one computer to another. It is then interpreted using a JVM.
Object Code :The conversion of high-level language to a machine code with help of a translator(compiler/interpretor)is known as Object code.
Java Virtual Machine (JVM) :It is a virtual processor(a program) which processes byte code to machine code for various platforms. So ,Java Interpreter is known as JVM.
IDE : An integrated development environment (IDE) or interactive development environment is a software application that provides comprehensive facilities to computer programmers for software development. An IDE normally consists of a source code editor, build automation tools and a debugger. Example Bluej, Eclipse, Net beans
Attribute : It is the state on which Objects differ. It deals with the contents of an object to make each object distinct.(belongings of a class) basically it is a value given to the state.
User Defined Data Type :Class is considered as User defined data type. User can use a class to create a new data type with some certain characteristics and behavior. So class is called user defined data type.
Reusability : The process of adding some essential features to a class without modifying its contents. It can be done by inheritance.
Applet :An Applet is written program in java language that can be included in an HTML page.
Case Sensitive : It is a Feature of Java Programming. It differentiates between lower case and upper case Letters.
Keywords : Keywords are preserved words which cannot be used as identifiers. They are reserved words of java which carry out a value/function/task. They have a special meaning.
Java libraries :A java Library is a set of packages .Each package is made for a purpose. It is a collection of similar classes. Ex:java.lang, java.io,java.util,etc.
Comment : Comments are used to tell the user about the purpose and action of different steps in the program. Comments increase the readability of the program. Comments are executed during the program.