Java Data Types: Understanding Primitive Data Types in Java, Summaries of Russian

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Java Fundamental

CLASS- 3

Data Types- 1

Data types in Java

In java, every variable should have some type, which is called data type, which specify the different sizes and values that can be stored in the variable. There are two types of data types in Java:

• Primitive data types: The primitive data types include boolean, char, byte, short, int, long, float and double.
• Non-primitive data types: The non-primitive data types include Classes, Interfaces, and Arrays.

Primitive data types

There are 8 types of primitive data types:

• boolean data type non-numeric
• char data type
• short data type
• int data type integral
• long data type
• byte data type
• float data type floating point
• double data type

Primitive data types

Data Type Default size boolean 1 bit char 2 byte byte 1 byte short 2 byte int 4 byte long 8 byte float 4 byte double 8 byte

Char Data Type

The char data type is a single 16-bit Unicode character. Its value-range lies between '\u0000' (or 0) to '\uffff' (or 65, inclusive).The char data type is used to store characters. Example: char letterA = 'A'

Short Data Type

The short data type is a 16-bit signed two's complement integer. Its value-range lies between - 32,768 to 32,767 (inclusive). Its minimum value is - 32,768 and maximum value is 32,767. Its default value is 0. The short data type can also be used to save memory just like byte data type. A short data type is 2 times smaller than an integer. Example: short s = 10000, short r = - 5000

Long Data Type

The long data type is a 64-bit two's complement integer. Its value-range lies between - 9,223,372,036,854,775,808(-2^63) to 9,223,372,036,854,775,807(2^63 - 1)(inclusive). Its minimum value is - 9,223,372,036,854,775,808and maximum value is 9,223,372,036,854,775,807. Its default value is 0. The long data type is used when you need a range of values more than those provided by int. Example: long a = 100000L, long b = - 200000L

Byte Data Type

The byte data type is an example of primitive data type. It is a 8-bit signed two's complement integer. Its value-range lies between - 128 to 127 (inclusive). Its minimum value is - 128 and maximum value is 127. Its default value is 0. The byte data type is used to save memory in large arrays where the memory savings is most required. It saves space because a byte is 4 times smaller than an integer. It can also be used in place of "int" data type. Example: byte a = 10, byte b = - 20

Double data type

The double data type is a double-precision 64- bit floating point. Its value range is unlimited. The double data type is generally used for decimal values just like float. The double data type also should never be used for precise values, such as currency. Its default value is 0.0d. Example: double d1 = 12.

Pay attention !!

Why char uses 2 byte in java and what is \u0000? It is because java uses Unicode system not ASCII code system. The \u0000 is the lowest range of Unicode system. Unicode is a universal international standard character encoding that is capable of representing most of the world's written languages.

Pay attention !!

Solution To solve these problems, a new language standard was developed i.e. Unicode System. In Unicode, character holds 2 byte, so java also uses 2 byte for characters. lowest value: \u highest value: \uFFFF

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