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Java Data Types

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Java programming language is a language in which all the variables must be declared first and then to be used.

Java Data Types

     

Java programming language is a language in which all the variables must be declared first and then to be used. That means to specify the name and the type of the variable. This specifies that Java is a strongly-typed programming language. Like

  int pedal = 1;

This shows that there exists a field named 'pedal' that holds a data as a numerical value '1'. The values contained by the variables determines its data type and to perform the operations on it.
There are seven more primitive data types which are supported by Java language programming in addition to int. A primitive data type is a data type which is predefined in Java. Following are the eight primitive data types:

int
It is a 32-bit signed two's complement integer data type. It ranges from -2,147,483,648 to 2,147,483,647. This data type is used for integer values. However for wider range of values use long.

byte
The byte data type is an 8-bit signed two's complement integer. It ranges from -128 to127 (inclusive). We can save memory in large arrays using byte. We can also use byte instead of int  to increase the limit of the code.

short
The short data type is a 16-bit signed two's complement integer. It ranges from -32,768 to 32,767. short is used to save memory in large arrays.

long
The long data type is a 64-bit signed two's complement integer. It ranges from -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807. Use this data type with larger range of values.  

float
The float data type is a single-precision 32-bit IEEE 754 floating point. It ranges from 1.40129846432481707e-45 to 3.40282346638528860e+38 (positive or negative). Use a float (instead of double) to save memory in large arrays. We do not use this data type for the exact values such as currency. For that we have to use
java.math.BigDecimal class

double
This data type is a double-precision 64-bit IEEE 754 floating point. It ranges from 4.94065645841246544e-324d to 1.79769313486231570e+308d (positive or negative). This data type is generally the default choice for decimal values. 

boolean
The boolean data type is 1-bit  and has only two values: true and false. We use this data type for conditional statements. true and false are not the same as True and False. They are defined constants of the language. 

char
The char data type is a single 16-bit, unsigned Unicode character. It
ranges from 0 to 65,535. They are not same as ints, shorts etc.

The following table shows the default values for the data types:

 Keyword  Description   Size/Format
 byte  Byte-length integer  8-bit two's complement
 short   Short integer  16-bit two's complement
 int  Integer   32-bit two's complement
 long   Long integer   64-bit two's complement
 float  Single-precision floating point  32-bit IEEE 
 double  Double-precision floating point  64-bit IEEE 
 char   A single character   16-bit Unicode character
 boolean   A boolean value (true or false)   true or false

When we declare a field it is not always essential that we initialize it too. The compiler sets a default value to the fields which are not initialized which might be zero or null. However this is not recommended. 

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Posted on: June 9, 2007

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Comments
amar
August 25, 2011
data type in java

sir.. what is the data type for number+charactor like0113bg01
manish
September 2, 2011
java

nice
PREM
February 9, 2012
dtatypes in java

how to understand
montish raj
May 30, 2012
data types

describe it briefly
anitha
July 18, 2012
computer science

wt is tha imporent in java data types
Tarun
August 8, 2012
vry helpfull

THANX ... These r really helpful to me ...
vinokamaraj
August 10, 2012
frnd

well
arunraj
September 25, 2012
Data type in java

what is the exact datatype for the string "00101110" in java?
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