看到一个有意思的点, openjdk里如何定义class相关方法

源码地址：http://hg.openjdk.java.net/jdk10/jdk10/jdk/file/777356696811/src/java.base/share/native/libjava/Class.c

#define OBJ "Ljava/lang/Object;"
#define CLS "Ljava/lang/Class;"
#define CPL "Ljdk/internal/reflect/ConstantPool;"
#define STR "Ljava/lang/String;"
#define FLD "Ljava/lang/reflect/Field;"
#define MHD "Ljava/lang/reflect/Method;"
#define CTR "Ljava/lang/reflect/Constructor;"
#define PD  "Ljava/security/ProtectionDomain;"
#define BA  "[B"

static JNINativeMethod methods[] = {
    {"getName0",         "()" STR,          (void *)&JVM_GetClassName},
    {"getSuperclass",    "()" CLS,          NULL},
    {"getInterfaces0",   "()[" CLS,         (void *)&JVM_GetClassInterfaces},
    {"isInterface",      "()Z",             (void *)&JVM_IsInterface},
    {"getSigners",       "()[" OBJ,         (void *)&JVM_GetClassSigners},
    {"setSigners",       "([" OBJ ")V",     (void *)&JVM_SetClassSigners},
    {"isArray",          "()Z",             (void *)&JVM_IsArrayClass},
    {"isPrimitive",      "()Z",             (void *)&JVM_IsPrimitiveClass},
    {"getModifiers",     "()I",             (void *)&JVM_GetClassModifiers},
    {"getDeclaredFields0","(Z)[" FLD,       (void *)&JVM_GetClassDeclaredFields},
    {"getDeclaredMethods0","(Z)[" MHD,      (void *)&JVM_GetClassDeclaredMethods},
    {"getDeclaredConstructors0","(Z)[" CTR, (void *)&JVM_GetClassDeclaredConstructors},
    {"getProtectionDomain0", "()" PD,       (void *)&JVM_GetProtectionDomain},
    {"getDeclaredClasses0",  "()[" CLS,      (void *)&JVM_GetDeclaredClasses},
    {"getDeclaringClass0",   "()" CLS,      (void *)&JVM_GetDeclaringClass},
    {"getSimpleBinaryName0", "()" STR,      (void *)&JVM_GetSimpleBinaryName},
    {"getGenericSignature0", "()" STR,      (void *)&JVM_GetClassSignature},
    {"getRawAnnotations",      "()" BA,        (void *)&JVM_GetClassAnnotations},
    {"getConstantPool",     "()" CPL,       (void *)&JVM_GetClassConstantPool},
    {"desiredAssertionStatus0","("CLS")Z",(void *)&JVM_DesiredAssertionStatus},
    {"getEnclosingMethod0", "()[" OBJ,      (void *)&JVM_GetEnclosingMethodInfo},
    {"getRawTypeAnnotations", "()" BA,      (void *)&JVM_GetClassTypeAnnotations},
};