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In Java, size doesn't matter

Can you ascertain the size of a primitive in Java?

By Tony Sintes, JavaWorld.com, 09/29/00

Is there a method in Java for determining the size of a primitive type, similar to C++'s sizeof operator?

The short answer: you can't find the size of a Java primitive type through a sizeof operator. Instead, all primitive types have a fixed size. Java was designed in this way to facilitate portability. Because Java specifies the primitive size up front, you can write a Java program and run it reliably on any JVM. If the designers had chosen to not define the size of primitive types, a program that ran on one hardware architecture could fail on another.

Another reason for a lack of sizeof: Java handles all memory access for you. As such, there is no need to find the sizeof some primitive or object in order to allocate a space of memory for it.

Nonetheless, times do arise when you will need to know the size of a primitive. For those times, I give you the following table:

Type	Size
boolean	1 bit
char	16 bit
byte	8 bit
short	16 bit
int	32 bit
long	64 bit
float	32 bit
double	64 bit
The sizes of the various Java primitives

 

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