Core Java™ 2 Volume II - Advanced Features, Seventh Edition

Numeric Parameters and Return Values

When passing numbers between C and the Java programming language, you should understand which types correspond to each other. For example, although C does have data types called int and long, their implementation is platform dependent. On some platforms, ints are 16-bit quantities, and on others they are 32-bit quantities. In the Java platform, of course, an int is always a 32-bit integer. For that reason, the Java Native Interface defines types jint, jlong, and so on.

Table 11-1 shows the correspondence between Java types and C types.

Table 11-1. Java Types and C Types

Java Programming Language	C Programming Language	Bytes
boolean	jboolean	1
byte	jbyte	1
char	jchar	2
short	jshort	2
int	jint	4
long	jlong	8
float	jfloat	4
double	jdouble ...