Java - long - Long (integer 64 bit)
Table of Contents
1 - About
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
2 - Articles Related
3 - Implementation
3.1 - 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 | <math>-2^{31}</math>
-2,147,483,648 | <math>+2^{31}-1</math>
-2,147,483,647 |
| long | Long | 64 bits | <math>-2^{63}</math>
-9,223,372,036,854,775,807 | <math>+2^{63-1}</math>
4.611.686.018.427.387.904 |
3.2 - Long
- java/util/concurrent/atomic/AtomicLong - A long value that may be update atomically - support increment function also
- java/util/concurrent/atomic/LongAccumulator
4 - Management
4.1 - Initialization
- From a literal
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);
4.2 - Operation
Number - (Arithmetical | Numerical | Mathematical) Operators on long
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
4.3 - To Int
- from a long object to an integer
Long theLong;
Integer i = theLong.intValue()
- or from a long primitive
Math.toIntExact(long)