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 LanguageC Programming LanguageBytes
booleanjboolean1
bytejbyte1
charjchar2
shortjshort2
intjint4
longjlong8
floatjfloat4
doublejdouble ...

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