CORE JAVA
DATA TYPES:
There are two data types available in Java
· Primitive Data Types
· Reference/Object Data Types
Primitive Data Types:
byte
l Byte data type is an 8-bit signed two's complement integer
l Minimum value is -128 (-2^7)
l Maximum value is 127 (inclusive)(2^7 -1)
l Default value is 0
l Byte data type is used to save space in large arrays, mainly in place of integers, since a byte is four times smaller than an integer.
l Example: byte a = 100, byte b = -50
short
l Short data type is a 16-bit signed two's complement integer
l Minimum value is -32,768 (-2^15)
l Maximum value is 32,767 (inclusive) (2^15 -1)
l Short data type can also be used to save memory as byte data type. A short is 2 times smaller than an integer
l Default value is 0.
l Example: short s = 10000, short r = -20000
int
l Int data type is a 32-bit signed two's complement integer.
l Minimum value is - 2,147,483,648 (-2^31)
l Maximum value is 2,147,483,647(inclusive) (2^31 -1)
l Integer is generally used as the default data type for integral values unless there is a concern about memory.
l The default value is 0
l Example: int a = 100000, int b = -200000
long
l Long data type is a 64-bit signed two's complement integer
l Minimum value is -9,223,372,036,854,775,808(-2^63)
l Maximum value is 9,223,372,036,854,775,807 (inclusive)(2^63 -1)
l This type is used when a wider range than int is needed
l Default value is 0L
l Example: long a = 100000L, long b = -200000L
float
l Float data type is a single-precision 32-bit IEEE 754 floating point
l Float is mainly used to save memory in large arrays of floating point numbers
l Default value is 0.0f
l Float data type is never used for precise values such as currency
l Example: float f1 = 234.5f
double
l double data type is a double-precision 64-bit IEEE 754 floating point
l This data type is generally used as the default data type for decimal values, generally the default choice
l Double data type should never be used for precise values such as currency
l Default value is 0.0d
l Example: double d1 = 123.4
boolean
l boolean data type represents one bit of information
l There are only two possible values: true and false
l This data type is used for simple flags that track true/false conditions
l Default value is false
l Example: boolean one = true
char
l char data type is a single 16-bit Unicode character
l Minimum value is '\u0000' (or 0)
l Maximum value is '\uffff' (or 65,535 inclusive)
l Char data type is used to store any character
l Example: char letterA = 'A'
Reference/Object Data Types:
l Class objects and various type of array variables come under reference datatype.
l Default value of any reference variable is null.
Java Literals:
A literal is a source code representation of a fixed value. They are represented directly in the code without any computation.
Literals can be assigned to any primitive type variable. For example −
byte a = 68;char a = 'A'
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