Java programming language introduction.

Java Programming Language: Java is strongly and statically typed, object oriented, class based, general purpose programming language.

By strongly and statically typed we mean that....

Programming language is set of rules defined to write the instructions for program which are intended for performing some specific task for machines or computers or any electronic devices like calculator.

Program is set of instructions which are written by using some specific programming language to perform some specific task.

Java is general purpose and high level programming language. By general purpose we mean that you can use Java programming language to develop some application but you cannot use it as research language like C or C++. By high level programming language we mean that Java language is not directly understood by computers or machines. To make Java understood by computers or machines we have to use some system software like Compiler and Interpreter.

In the computer science we have following types of languages:

1.     Machine Level Programming Languages: Machine level programming languages are those languages which are directly understood by the machines or computers. Since, machines can understand the languages of 0s and 1s; these languages use these two symbols only. Machine level programming languages are difficult to understand by the programmer as it is difficult to remember all the combinations of 0s and 1s to produce particular instructions. In early ages if computers when computers were not so common, such languages were being used.

2.     Assembly Language: Since machine languages were difficult to understand by humans; computer scientist developed programming languages by using mnemonics in English like language. Since humans or programmers can understand mnemonics (some specific words to define some particular action) it is easier to understand and to write programs in Assembly language. But computers were still unable to understand the assembly language directly so they developed system software called assembler which is responsible for converting the assembly language to the language understood by computers. So the assemblers are the program which converts assembly language code into machine code.

3.     High Level Language: But still assembly languages were not so easy to understand and program as it contained only small amount of words (mnemonics) which can be understood by the programmers. To solve this problem computer scientist developed some high level languages including C, C++ etc. High level machine language contains words from English language are used, which are easy to remember by the programmers. But computers cannot understand the high languages directly so to make it understood by the computers we use the concept of system software like Compiler or Interpreters. The task of both complier and interpreter is to convert high language into the language understood by the computers. The difference between compiler and interpreter is that compiler translates high level programming language to the language understood by the computer in one shot while the interpreter does the same job line by line.

So Java is high level programming language which uses compiler and interpreter to convert the java program into the machine code, how? We will see it later.