Starting Java Language :-

Character set of Java :- 

    Alphabets :---         A , B , C ,...................  X , Y , Z

    Digits       :----        0,1,2,3,4,5,6,7,8,9

    Special Symbol :-  ~!@#$%*()_=+-*/." " ' ': ; {} [] <>

Variable :-  It is an entity whose value may change during execution.

Keywords :- It is an entity whose meaning is already given by java. ex. class is only use to create a                             class.

Values :-     These are the actual values which get stored in memory.

Constants :-  It is an entity whose value can not be change.

Instructions :- A computer performs tasks on the basis of the instruction provided. ex. int a=10;

Program :- A computer program is a set of instructions