java data types | java data types in hindi

Java Data type

 

Every variable in java have data type. Data type specify the size and the type of value that can be stored. Java Language is rich in its data types. The variety of data type allow the programmer to select the type appropriate to the need of the application. 

java datatype

Data type defines the values that a variable can take, for example if a variable has int data type, it can only take integer values. In java we have two categories of data type: 1) Primitive data types 2) Non-primitive data types – Arrays and Strings are non-primitive data types, we will discuss them later in the coming tutorials. Here we will discuss primitive data types and literals in Java.

Java has two categories of data:

1) Primitive data types

In Java, we have eight primitive data types: boolean, char, byte, short, int, long, float and double. Java developers included these data types to maintain the portability of java as the size of these primitive data types do not change from one operating system to another.

byte, short, int and long data types are used for storing whole numbers.

float and double are used for fractional numbers.

char is used for storing characters(letters).

boolean data type is used for variables that holds either true or false.

byte:

This can hold whole number between -128 and 127. Mostly used to save memory and when you are certain that the numbers would be in the limit specified.  
Example:

class JavaExample {

    public static void main(String[] args) {

            byte num;

            num = 113;

            System.out.println(num);

    }

}

short:

This is greater than byte in terms of size and less than integer. Its range is -32,768 to 32767.
Default size of this data type: 2 byte

Short num=45678

Integer:

 Used when short is not large enough to hold the number, it has a wider range: -2,147,483,648 to 2,147,483,647
Default size: 4 byte
Default value: 0
Example:

 

class JavaExample {

    public static void main(String[] args) {

            short num;

            num = 150;

            System.out.println(num);

    }

}

long:

Used when int is not large enough to hold the value, it has wider range than int data type, ranging from -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807.

Example:

class JavaExample {

    public static void main(String[] args) {

            long num = -12332252626L;

            System.out.println(num);

    }

}

float:

Sufficient for holding 6 to 7 decimal digits
size: 4 bytes

Example

class JavaExample {

    public static void main(String[] args) {

            float num = 19.98f;

            System.out.println(num);

    }

}

boolean:

 holds either true of false.

Example

class JavaExample {

    public static void main(String[] args) {

            boolean b = false;

            System.out.println(b);

    }

}

character:

Hold character

Size:2byte

Example

class JavaExample {

    public static void main(String[] args) {

            char ch = 'Z';

            System.out.println(ch);

    }

}

  

o  Non-Primitive Data Type or Object Data type: 

The primitive data types include byte, int, long, short, float, double, and char. They are part of the core of Java and you don't need anything special to use them. For example, the following declares a long variable for a partNumber:

     A data type that is primitive, such as the long variable, actually stores        the value. If we give a value to the partNumber value, for example 4030023, that is what Java stores.

  Reference types can be a class, interface, or array variable. Remember  that a class is a set of plans for a given object. There are thousands of  tree objects, but the parent set of plans would belong in the tree class. Variables can exist inside the tree class, such as height or tree type. These are reference variables.

An array is a single object that contains multiple values of the same type. We could have declared our integer for partNumbers as an array to hold a given number of partNumbers in a single object.

There are three type of non-primitive data type.

Class, Interface, Array etc.

Class Data Types

Let's say we declare a new class called Product:

 

class in java

In order to create a new non-primitive or reference variable for this class, we have to create a new instance of the Product class. The new keyword is used to create an object. Look at the following example where we'll be creating a new Product called car wax.

The Java code is as follows:

java

 

So now we have a variable of carWax: But it's really an instance of the Product class, and not a set value like the primitive variables.

Interface Data Types

An interface is like a dashboard or control panel for a class. It has the buttons, but the function is elsewhere. We won't go into detail on implementing interfaces since the focus is on the interface as a non-primitive, or reference, data type.

java datatype