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Primitives And Wrappers

8 Primitive Types

1. Short answer

Java has 8 primitive data types:

  1. byte -> 8-bit integer, range: -128 to 127
  2. short -> 16-bit integer, range: -32,768 to 32,767
  3. int -> 32-bit integer, range: -231 to 231 -1
  4. long -> 64-bit integer, range: -263 to 263 -1
  5. float -> 32-bit floating-point number
  6. double -> 64-bit floating-point number
  7. char -> 16-bit Unicode character
  8. boolean -> Represents true or false
    These types are used to store simple values and are more memory-efficient than objects.

2. Long answer

In Java, most work is done with primitives. These primitive data types are the foundation of all other types.

  • They are used to store simple values such as numbers and characters.
  • They are stored directly in memory and are accessed faster than non-primitive data types.

There are eight primitive data types in Java: byte, short, int, long, float, double, char and boolean.

The size and range of values that can be stored in a primitive data type depending on the type itself. For example, a boolean can only hold the values true or false, while a long can hold values from -263 to 263-1.

Hence, the 8 primitive data types in Java are categorized into 4 types.

  1. Integer types - byte, short, int, and long.
  2. Floating point types - float and double.
  3. Character type - char.
  4. Boolean type - boolean.

Illustration

Tabular chart

Let us see the bytes size, default value, min and max and ranges of all the primitive data types.

1. byte

A byte is an 8-bit signed integer occupies 1 byte, default value is 0, and it can store a minimum value of -2^7 or -128 and a maximum value of (2^7 - 1) or 127.

The maximum and minimum values of byte can be found at:

byte high = Byte.MAX_VALUE;   // high == 127
byte low = Byte.MIN_VALUE;    // low == -128

2. short

A short is a 16-bit signed integer.

  • Occupies 2 bytes.
  • The default value is 0.
  • It can store a min value of -2^15 or -32768 and a maximum value of (2^15 - 1) or 32767.
short A = -48;
short B = 987;
short C = 17;

short add = (short) (B + C);
short subtract = (short) (B - C);

System.out.println(add); // 1004
System.out.println(subtract); // 970

The maximum and minimum values of short can be found at:

short high = Short.MAX_VALUE; // high == 32767
short low = Short.MIN_VALUE;  // low = -32768

3. int

This is one of Java's most used data types, storing 4 bytes of data. According to Java API, the Integer class wraps a value of the primitive type int in an object.

An int is a 32-bit signed integer.

  • Occupies 4 bytes.
  • The default value is 0.
  • It can store a min value of -2^31 or -2B and a maximum value of (2^31 - 1) or 2B.
int A = -48;
int B = 987;
int C = 17;

int add = B + C;
int subtract = B - C;

System.out.println(add); // 1004
System.out.println(subtract); // 970

The maximum and minimum values of short can be found at:

int max = Integer.MAX_VALUE; // -2147483648
int min = Integer.MIN_VALUE; // 2147483647

4. long

By default, long is a signed integer (In Java 8, it can be either signed/unsigned).

Signed: It can store a minimum of 263 and a maximum of 263 - 1).
Unsigned: It can store a minimum value of 0 and a maximum value of 264 - 1).

  • Occupies 8 bytes.
  • The default value is 0L.

If you assign long A = 100, Java assumes it as a int type. Appending L makes it a long.

long A = -42;
long B = 284;
long C = 73;
long bigNumber = 549755813888L;

long addedLongs = B + C; // 284 + 73 = 357
long subtractedLongs = B - C; // 284 - 73 = 211

System.out.println(addedLongs); // 357
System.out.println(subtractedLongs); // 211

The maximum and minimum values of long can be found at:

// Max and Min
long high = Long.MAX_VALUE; // high == 9223372036854775807L
long low = Long.MIN_VALUE;  // low == -9223372036854775808L
Note: Letter L appended at the end of the long literal is case insensitive, however it is good practice to use capital as it is easier to distinct from digit one.
2L == 2l // true

5. float

A float is a single-precision 32-bit floating point number.

  • Occupies 4 bytes.
  • The default value is `0.0F`.
  • It can store a min value of -2^149 and a maximum value of 2^127.

By default, decimals are interpreted as doubles. To create a float, append an f to the decimal literal.

A float is precise to roughly an error of 1 in 10 million.

Float.POSITIVE_INFINITY
Float.NEGATIVE_INFINITY
Float.NaN

NaN stands for the results of an operation that cannot be determined. Such as dividing two infinite values.

float f1 = 0f;
float f2 = -0f;
System.out.println(f1 == f2); // true
System.out.println(1f / f1); // Infinity
System.out.println(1f / f2); // -Infinity
System.out.println(Float.POSITIVE_INFINITY / Float.POSITIVE_INFINITY); // NaN

0f and -0f are different but == yields true.

// addition
float add = 37.2f + -2.6f; // result: 34.6
System.out.println(add);

// subtraction
float subtract = 45.1f - 10.3f; // result: 34.8
System.out.println(subtract);

// multiplication
float multiply = 26.3f * 1.7f; // result: 44.71
System.out.println(multiply);

// division
float division = 37.1f / 4.8f; // result: 7.729166
System.out.println(division);

// modulus
float modulus = 37.1f % 4.8f; // result: 3.4999971
System.out.println(modulus);

6. double

A double is a double-precision 64-bit floating point number.

  • Occupies 8 bytes.
  • The default value is `0.0D`.
  • It can store a min value of -2^1074 and a maximum value of 2^1023.
double d1 = 0d;
double d2 = -0d;
System.out.println(d1 == d2); // true  
System.out.println(1d / d1); // Infinity  
System.out.println(1d / d2); // -Infinity 
System.out.println(Double.POSITIVE_INFINITY / Double.POSITIVE_INFINITY); // NaN
double A = -7162.37;
double B = 974.21;
double C = 658.7;

double addedDoubles = B + C; // 315.51 
double subtractedDoubles = B - C; // 1632.91

double scientificNotationDouble = 1.2e-3; // 0.0012

7. char

A char can store a single 16-bit Unicode character. A character literal is enclosed in single quotes.

  • Occupies 2 bytes.
  • The default value is 0.
  • It can store a minimum value of \u0000 ( 0 in the decimal representation, also called the null character) and the maximum of \uffff or (2^16 - 1).
  • The char values are A, B, a, d, etc.
char myChar = 'u'; // 'u'
char myChar2 = '5'; // '5'
char myChar3 = 65; // 'A'

8. boolean

A boolean can store one of two values, either true or false.

  • Occupies 1 bytes.
  • The default value is false.
  • There is no min or max for boolean data type.
boolean a = true; // true
boolean b = false; // false

boolean notA = !a; // false
boolean notB = !b; // true

boolean aAndB = a && b; // false
boolean aOrB = a || b; // true

boolean aXorB =a ^ b; // true