JAVA keywords, Literals, identifiers, Separators, Operators & Data Types

KEYWORDS

Keywords are reserved words that convey a special meaning to the language
compiler. 

IDENTIFIERS

Identifiers are the fundamental building blocks of a program and are used
for general terminology for variables, objects and classes (Don’t worry we
will discuss about them very soon).

They should be created adhering to the following set of rules:-

1. They can have alphabets, digits and doller sign.
2. They must not be a keyword or boolean or a null literal.
3. They must not begin with a digit.

LITERALS

Literals (also called consonants) are data item that are fixed data values.

Following are the types of literals:-

1. Integer literal (whole numbers without any fractional part)
2. Floating literal (also called Real Literals, they have fractional parts)
3. Boolean literal ( represented by true or false)
4. Character literal (one character enclosed in single quotes)
5. String literal (sequence of zero or more characters surrounded by double quotes)
6.  Null literal

SEPERATORS/ PUNCTUATORS

The following are the ASCII (American Standard Code for Information Exchange):-

(  ) {   } [ ]     ; , .

OPEARTORS

These are tools which manipulate data or which are used for calculations. It is a symbol which represents a particular operation to be performed on data values.

DATA TYPES

Java has two types of data types:-

1. Primitive datatype which is a part of the language.
2. Reference datatype are derived from the above. These can be classes, interfaces or arrays. It is used to store address of the objects (What are objects? Hold your horses for God’s sake!!).