Java - long - Long (integer 64 bit)

A long variable is an integer on 64 bit. (May be Computer Number - Float64 (64-bit or double precision) floating-point number)

For an integer on 32bit, see Java - Integer

The primitive wrapper Long is a subclass of Number in java

Implementation

Primitive Integer

Long is an integer that is encoded with 64 bit but you have also int on 32 bit.

Primitive Type Primitive Wrapper Stored in a word of min max
int Integer 32 bits $-2^{31}$
-2,147,483,648
$+2^{31}-1$
-2,147,483,647
long Long 64 bits $-2^{63}$
-9,223,372,036,854,775,807
$+2^{63-1}$
‭4.611.686.018.427.387.904‬

Management

Initialization

long = 1.073.741.824L;

• From a variable
long = (long)a;

• from an integer
Long i = theinteger.longValue()

• from an int
Long i = Long.valueOf(3);


Operation

The operations are done in the largest data type required to handle all of the current values.

For the below mathematics Operations The operation is a
int (operator) int integer operation
int (operator) long long operation

Example:

• a long operation
long i = (int)1 * (long)2

• a int operation
long i = (int)1 * (int)2


To Int

Long theLong;
Integer i = theLong.intValue()

• or from a long primitive
Math.toIntExact(long)