| Java Primitive Types | Signature | JNI Primitive Types | Description |
| boolean | Z | jboolean |
unsigned 8 bits
JNI_TRUE JNI_FALSE |
| byte | B | jbyte | signed 8 bits |
| char | C | jchar | unsigned 16 bits |
| short | S | jshort | signed 16 bits |
| int | I | jint | signed 32 bits |
| long | J | jlong | signed 64 bits |
| float | F | jfloat | 32 bits |
| double | D | jdouble | 64 bits |
| void | V | ||
| ? extends java.lang.Object | Start with "L" and end with ";", in the middle are the package and class names separated by "/". For example: "Ljava/lang/String;", if it is a nested class, use "$" to Indicates nesting. For example: "Ljava/lang/System$LoggerFinder;". |