Java Data types

Java Data types

Java is a strongly typed language, so you must declare a type for each variable.

There are 8 basic types of Java, including: integer 4, floating-point 2, Unicode character 1, and Boolean-value type 1 .

Integral type

Java integral type

Type	Storage space	Range of values
Int	4 bytes	-2147483648 ~ 2147483647
Short	2 bytes	-32768 ~ 32767
Long	8 bytes	-9223372036854775808 ~ 9223372036854775807
Byte	1 bytes	-128 ~ 127

Floating-point type: Used to represent a numeric value with a decimal part.

Java floating-point type

type	storage space	value range
float	4 bytes	approximately ±3.40282347e + 38F (number of significant digits is 6~7 bit)
double	8 bytes	approximately ±1.79769313486231570e + 308 (significant digits 15 bits)

A value of type float has a suffix f, (for example, 3.14F), and if a floating-point value without an F-suffix defaults to a double type, a double-type floating-point value can be appended with a suffix D, such as 3.14D.

Floating-point values do not apply to financial calculations with incoming errors, for example: 2.0-1.1 will appear = 0.89999999999999 instead of 0.9, which is mainly due to the fact that floating-point values are represented by a binary system, while in binary systems it is not possible to accurately represent a fraction of 1/ 10, it is as if the decimal does not accurately represent 1/3. If you need to have no rounding errors in the numerical calculations, you should use the BigDecimal class.

Char type

The char type is used to represent a single character, and its Unicode encoding unit can be represented as a hexadecimal value ranging from \u0000 to \UFFFF. A char type is a deprecated numeric type, preferably a string that needs to be processed in an abstract data type.

Boolean type (Boolean type)

A Boolean (Boolean) type has only two values: True and False. These two values are used to determine whether the logic is true or false. An integer value and a Boolean value cannot be converted to each other in Java.

Java Data types