Java,Variables are not anything but reserved reminiscence locations to keep values. This way that when you create a variable you reserve some space inside the memory.
Based at the information type of a variable, the working machine allocates reminiscence and decides what can be saved within the reserved memory. Therefore, via assigning one of a kind records kinds to variables, you can shop integers, decimals, or characters in those variables.
There are information types to be had in Java −
- Primitive Data Types
- Reference/Object Data Types
Java,Primitive Data Types
There are eight primitive datatypes supported by way of Java. Primitive datatypes are predefined through the language and named via a key-word. Let us now investigate the eight primitive statistics sorts in element.
- Byte data type is an 8-bit signed two’s complement integer
- Minimum value is -128 (-2^7)
- Maximum value is 127 (inclusive)(2^7 -1)
- Default value is 0
- 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.
- Example: byte a = 100, byte b = -50
- Short data type is a 16-bit signed two’s complement integer
- Minimum value is -32,768 (-2^15)
- Maximum value is 32,767 (inclusive) (2^15 -1)
- Short data type can also be used to save memory as byte data type. A short is 2 times smaller than an integer
- Default value is 0.
- Example: short s = 10000, short r = -20000
- Int data type is a 32-bit signed two’s complement integer.
- Minimum value is – 2,147,483,648 (-2^31)
- Maximum value is 2,147,483,647(inclusive) (2^31 -1)
- Integer is generally used as the default data type for integral values unless there is a concern about memory.
- The default value is 0
- Example: int a = 100000, int b = -200000
- Long data type is a 64-bit signed two’s complement integer
- Minimum value is -9,223,372,036,854,775,808(-2^63)
- Maximum value is 9,223,372,036,854,775,807 (inclusive)(2^63 -1)
- This type is used when a wider range than int is needed
- Default value is 0L
- Example: long a = 100000L, long b = -200000L
- This data type is a single-precision 32-bit IEEE 754 floating point
- Float is mainly used to save memory in large arrays of floating point numbers
- Default value is 0.0f
- Float data type is never used for precise values such as currency
- Example: float f1 = 234.5f
- double data type is a double-precision 64-bit IEEE 754 floating point
- This data type is generally used as the default data type for decimal values, generally the default choice
- Double data type should never be used for precise values such as currency
- Default value is 0.0d
- Example: double d1 = 123.4
- boolean data type represents one bit of information
- There are only two possible values: true and false
- This data type is used for simple flags that track true/false conditions
- Default value is false
- Example: boolean one = true
- char data type is a single 16-bit Unicode character
- Minimum value is ‘\u0000’ (or 0)
- Maximum value is ‘\uffff’ (or 65,535 inclusive)
- Char data type is used to store any character
- Example: char letterA = ‘A’
- Reference variables are created the use of defined constructors of the training. They are used to get entry to gadgets. These variables are declared to be of a specific type that can not be modified. For example, Employee, Puppy, etc.
- Class items and diverse sort of array variables come below reference datatype.
- Default price of any reference variable is null.
- A reference variable may be used to refer any item of the declared kind or any like minded type.
- Example: Animal animal = new Animal(“giraffe”)
A literal is a source code illustration of a set price. They are represented without delay within the code without any computation.
Literals may be assigned to any primitive type variable. For example −
byte a = 68; char a = ‘A’;
Byte, int, lengthy, and quick may be expressed in decimal(base 10), hexadecimal(base 16) or octal(base eight) range systems as well.
Prefix 0 is used to indicate octal, and prefix 0x indicates hexadecimal when the usage of those quantity structures for literals. For instance −
int decimal = 100; int octal = 0144; int hexa = 0x64;
String literals in Java are unique like they’re in most other languages through enclosing a chain of characters among a pair of double costs. Examples of string literals are −
“Hello World” “two\nlines” “\”This is in quotes\””
String and char sorts of literals can incorporate any Unicode characters. For example −
char a = ‘\u0001’; String a = “\u0001”;
Java language supports few special escape sequences for String and char literals as nicely. They are −
|\r||Carriage return (0x0d)|
|\ddd||Octal character (ddd)|
|\uxxxx||Hexadecimal UNICODE character (xxxx)|