How to develop a java progam ?

The java development kit (JDK) provides all features to write programs. The JDK is available for system running Windows NT, Windows 95 and Solaris 2.3 or higher. Java applications are general programs written in the java language that do not require a browser to run. J2ee, java servlet are advance of java and it has jdbc dirver model.

  • The java program file saved as filename. Java
  • Compile program by javac filename. Java
  • Execute program by java filename

Types of feature available in java

Data types

Java provides different data types that include integer, float, character, Boolean.
  • Integers are used for storing integer values
  • Float is used to store number with decimal part
  • Character is used for storing individual characters
  • Boolean data types hold either a true or a false value

Variables

In variables java has three kinds of variables they are instance variables, local variables, class variables.
  • Instance variables are used to define attributes or the state of a particular objects.
  • Local variables are used inside blocks as counters or in methods as temporary variables.
  • Class variables are global to a class and to all the instances of the class.

Declaring variable

Variables can be declared anywhere in the method definition and can be initialized during their declaration.

Variable names

Variable names in java can start with a letter, an underscore, dollar sign but it cannot begin with a numbers.

Variable types

Variable types can be any data type that supports the eight primitive types, the names of class or interface and an array.

Assigning values

Values are assigned to variable using the assignment operator.

Literals

A literal represents a value of a certain type where the type describes the behavior of the value, there are different types of literals, and they are
  • Number
  • Character
  • Boolean
  • String

Expressions

Expressions are the simplest form of statements in java. These statements return a value that can be assigned to a variable.

Operators

Operators are special symbols used in expression; they include arithmetic operators, assignment operators, incrementing and decrementing operators, comparison operators, logical operators, bitwise operators, and operator precedence.

Programming constructs

Programming constructs in java are the If construct, conditional operator, while loop, do while loop, for loop, switch statement, break and continue statement.