Bluetooth Data Transfer Example

JNI Types and Data Structures

 

Table 3-1 Primitive Types and Native Equivalents

Java Type	Native Type	Description
boolean	jboolean	unsigned 8 bits
byte	jbyte	signed 8 bits
char	jchar	unsigned 16 bits
short	jshort	signed 16 bits
int	jint	signed 32 bits
long	jlong	signed 64 bits
float	jfloat	32 bits
double	jdouble	64 bits
void	void	N/A

 

Type Signatures

The JNI uses the Java VM’s representation of type signatures. Table 3-2 shows these type signatures.

Table 3-2 Java VM Type Signatures

Type Signature	Java Type
Z	boolean
B	byte
C	char
S	short
I	int
J	long
F	float
D	double    L fully-qualified-class ; fully-qualified-class [ type type[] ( arg-types ) ret-type method type For example, the Java method: long f (int n, String s, int[] arr); has the following type signature: (ILjava/lang/String;[I)J