最主要的就是jni.h文件了。

/*
 * Copyright (C) 2006 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/*
 * JNI specification, as defined by Sun:
 * http://java.sun.com/javase/6/docs/technotes/guides/jni/spec/jniTOC.html
 *
 * Everything here is expected to be VM-neutral.
 */

#ifndef JNI_H_
#define JNI_H_

#include <stdarg.h>

/*
 * Primitive types that match up with Java equivalents.
 */
#ifdef HAVE_INTTYPES_H
# include <inttypes.h>    /* C99 */
typedef uint8_t     jboolean;     /* unsigned 8 bits */
typedef int8_t      jbyte;      /* signed 8 bits */
typedef uint16_t    jchar;      /* unsigned 16 bits */
typedef int16_t     jshort;     /* signed 16 bits */
typedef int32_t     jint;       /* signed 32 bits */
typedef int64_t     jlong;      /* signed 64 bits */
typedef float       jfloat;     /* 32-bit IEEE 754 */
typedef double      jdouble;    /* 64-bit IEEE 754 */
#else
typedef unsigned char   jboolean;     /* unsigned 8 bits */
typedef signed char   jbyte;      /* signed 8 bits */
typedef unsigned short  jchar;      /* unsigned 16 bits */
typedef short       jshort;     /* signed 16 bits */
typedef int       jint;       /* signed 32 bits */
typedef long long     jlong;      /* signed 64 bits */
typedef float       jfloat;     /* 32-bit IEEE 754 */
typedef double      jdouble;    /* 64-bit IEEE 754 */
#endif

/* "cardinal indices and sizes" */
typedef jint      jsize;

#ifdef __cplusplus
/*
 * Reference types, in C++
 */
class _jobject {};
class _jclass : public _jobject {};
class _jstring : public _jobject {};
class _jarray : public _jobject {};
class _jobjectArray : public _jarray {};
class _jbooleanArray : public _jarray {};
class _jbyteArray : public _jarray {};
class _jcharArray : public _jarray {};
class _jshortArray : public _jarray {};
class _jintArray : public _jarray {};
class _jlongArray : public _jarray {};
class _jfloatArray : public _jarray {};
class _jdoubleArray : public _jarray {};
class _jthrowable : public _jobject {};

typedef _jobject*     jobject;
typedef _jclass*    jclass;
typedef _jstring*     jstring;
typedef _jarray*    jarray;
typedef _jobjectArray*  jobjectArray;
typedef _jbooleanArray* jbooleanArray;
typedef _jbyteArray*  jbyteArray;
typedef _jcharArray*  jcharArray;
typedef _jshortArray*   jshortArray;
typedef _jintArray*   jintArray;
typedef _jlongArray*  jlongArray;
typedef _jfloatArray*   jfloatArray;
typedef _jdoubleArray*  jdoubleArray;
typedef _jthrowable*  jthrowable;
typedef _jobject*     jweak;


#else /* not __cplusplus */

/*
 * Reference types, in C.
 */
typedef void*       jobject;
typedef jobject     jclass;
typedef jobject     jstring;
typedef jobject     jarray;
typedef jarray      jobjectArray;
typedef jarray      jbooleanArray;
typedef jarray      jbyteArray;
typedef jarray      jcharArray;
typedef jarray      jshortArray;
typedef jarray      jintArray;
typedef jarray      jlongArray;
typedef jarray      jfloatArray;
typedef jarray      jdoubleArray;
typedef jobject     jthrowable;
typedef jobject     jweak;

#endif /* not __cplusplus */

struct _jfieldID;             /* opaque structure */
typedef struct _jfieldID* jfieldID;   /* field IDs */

struct _jmethodID;            /* opaque structure */
typedef struct _jmethodID* jmethodID;   /* method IDs */

struct JNIInvokeInterface;

typedef union jvalue {
  jboolean  z;
  jbyte     b;
  jchar     c;
  jshort    s;
  jint    i;
  jlong     j;
  jfloat    f;
  jdouble   d;
  jobject   l;
} jvalue;

typedef enum jobjectRefType {
  JNIInvalidRefType = 0,
  JNILocalRefType = 1,
  JNIGlobalRefType = 2,
  JNIWeakGlobalRefType = 3
} jobjectRefType;

typedef struct {
  const char* name;
  const char* signature;
  void*     fnPtr;
} JNINativeMethod;

struct _JNIEnv;
struct _JavaVM;
typedef const struct JNINativeInterface* C_JNIEnv;

#if defined(__cplusplus)
typedef _JNIEnv JNIEnv;
typedef _JavaVM JavaVM;
#else
typedef const struct JNINativeInterface* JNIEnv;
typedef const struct JNIInvokeInterface* JavaVM;
#endif

/*
 * Table of interface function pointers.
 */
struct JNINativeInterface {
  void*     reserved0;
  void*     reserved1;
  void*     reserved2;
  void*     reserved3;

  jint    (*GetVersion)(JNIEnv *);

  jclass    (*DefineClass)(JNIEnv*, const char*, jobject, const jbyte*,
            jsize);
  jclass    (*FindClass)(JNIEnv*, const char*);

  jmethodID   (*FromReflectedMethod)(JNIEnv*, jobject);
  jfieldID  (*FromReflectedField)(JNIEnv*, jobject);
  /* spec doesn&#39;t show jboolean parameter */
  jobject   (*ToReflectedMethod)(JNIEnv*, jclass, jmethodID, jboolean);

  jclass    (*GetSuperclass)(JNIEnv*, jclass);
  jboolean  (*IsAssignableFrom)(JNIEnv*, jclass, jclass);

  /* spec doesn&#39;t show jboolean parameter */
  jobject   (*ToReflectedField)(JNIEnv*, jclass, jfieldID, jboolean);

  jint    (*Throw)(JNIEnv*, jthrowable);
  jint    (*ThrowNew)(JNIEnv *, jclass, const char *);
  jthrowable  (*ExceptionOccurred)(JNIEnv*);
  void    (*ExceptionDescribe)(JNIEnv*);
  void    (*ExceptionClear)(JNIEnv*);
  void    (*FatalError)(JNIEnv*, const char*);

  jint    (*PushLocalFrame)(JNIEnv*, jint);
  jobject   (*PopLocalFrame)(JNIEnv*, jobject);

  jobject   (*NewGlobalRef)(JNIEnv*, jobject);
  void    (*DeleteGlobalRef)(JNIEnv*, jobject);
  void    (*DeleteLocalRef)(JNIEnv*, jobject);
  jboolean  (*IsSameObject)(JNIEnv*, jobject, jobject);

  jobject   (*NewLocalRef)(JNIEnv*, jobject);
  jint    (*EnsureLocalCapacity)(JNIEnv*, jint);

  jobject   (*AllocObject)(JNIEnv*, jclass);
  jobject   (*NewObject)(JNIEnv*, jclass, jmethodID, ...);
  jobject   (*NewObjectV)(JNIEnv*, jclass, jmethodID, va_list);
  jobject   (*NewObjectA)(JNIEnv*, jclass, jmethodID, jvalue*);

  jclass    (*GetObjectClass)(JNIEnv*, jobject);
  jboolean  (*IsInstanceOf)(JNIEnv*, jobject, jclass);
  jmethodID   (*GetMethodID)(JNIEnv*, jclass, const char*, const char*);

  jobject   (*CallObjectMethod)(JNIEnv*, jobject, jmethodID, ...);
  jobject   (*CallObjectMethodV)(JNIEnv*, jobject, jmethodID, va_list);
  jobject   (*CallObjectMethodA)(JNIEnv*, jobject, jmethodID, jvalue*);
  jboolean  (*CallBooleanMethod)(JNIEnv*, jobject, jmethodID, ...);
  jboolean  (*CallBooleanMethodV)(JNIEnv*, jobject, jmethodID, va_list);
  jboolean  (*CallBooleanMethodA)(JNIEnv*, jobject, jmethodID, jvalue*);
  jbyte     (*CallByteMethod)(JNIEnv*, jobject, jmethodID, ...);
  jbyte     (*CallByteMethodV)(JNIEnv*, jobject, jmethodID, va_list);
  jbyte     (*CallByteMethodA)(JNIEnv*, jobject, jmethodID, jvalue*);
  jchar     (*CallCharMethod)(JNIEnv*, jobject, jmethodID, ...);
  jchar     (*CallCharMethodV)(JNIEnv*, jobject, jmethodID, va_list);
  jchar     (*CallCharMethodA)(JNIEnv*, jobject, jmethodID, jvalue*);
  jshort    (*CallShortMethod)(JNIEnv*, jobject, jmethodID, ...);
  jshort    (*CallShortMethodV)(JNIEnv*, jobject, jmethodID, va_list);
  jshort    (*CallShortMethodA)(JNIEnv*, jobject, jmethodID, jvalue*);
  jint    (*CallIntMethod)(JNIEnv*, jobject, jmethodID, ...);
  jint    (*CallIntMethodV)(JNIEnv*, jobject, jmethodID, va_list);
  jint    (*CallIntMethodA)(JNIEnv*, jobject, jmethodID, jvalue*);
  jlong     (*CallLongMethod)(JNIEnv*, jobject, jmethodID, ...);
  jlong     (*CallLongMethodV)(JNIEnv*, jobject, jmethodID, va_list);
  jlong     (*CallLongMethodA)(JNIEnv*, jobject, jmethodID, jvalue*);
  jfloat    (*CallFloatMethod)(JNIEnv*, jobject, jmethodID, ...);
  jfloat    (*CallFloatMethodV)(JNIEnv*, jobject, jmethodID, va_list);
  jfloat    (*CallFloatMethodA)(JNIEnv*, jobject, jmethodID, jvalue*);
  jdouble   (*CallDoubleMethod)(JNIEnv*, jobject, jmethodID, ...);
  jdouble   (*CallDoubleMethodV)(JNIEnv*, jobject, jmethodID, va_list);
  jdouble   (*CallDoubleMethodA)(JNIEnv*, jobject, jmethodID, jvalue*);
  void    (*CallVoidMethod)(JNIEnv*, jobject, jmethodID, ...);
  void    (*CallVoidMethodV)(JNIEnv*, jobject, jmethodID, va_list);
  void    (*CallVoidMethodA)(JNIEnv*, jobject, jmethodID, jvalue*);

  jobject   (*CallNonvirtualObjectMethod)(JNIEnv*, jobject, jclass,
            jmethodID, ...);
  jobject   (*CallNonvirtualObjectMethodV)(JNIEnv*, jobject, jclass,
            jmethodID, va_list);
  jobject   (*CallNonvirtualObjectMethodA)(JNIEnv*, jobject, jclass,
            jmethodID, jvalue*);
  jboolean  (*CallNonvirtualBooleanMethod)(JNIEnv*, jobject, jclass,
            jmethodID, ...);
  jboolean  (*CallNonvirtualBooleanMethodV)(JNIEnv*, jobject, jclass,
             jmethodID, va_list);
  jboolean  (*CallNonvirtualBooleanMethodA)(JNIEnv*, jobject, jclass,
             jmethodID, jvalue*);
  jbyte     (*CallNonvirtualByteMethod)(JNIEnv*, jobject, jclass,
            jmethodID, ...);
  jbyte     (*CallNonvirtualByteMethodV)(JNIEnv*, jobject, jclass,
            jmethodID, va_list);
  jbyte     (*CallNonvirtualByteMethodA)(JNIEnv*, jobject, jclass,
            jmethodID, jvalue*);
  jchar     (*CallNonvirtualCharMethod)(JNIEnv*, jobject, jclass,
            jmethodID, ...);
  jchar     (*CallNonvirtualCharMethodV)(JNIEnv*, jobject, jclass,
            jmethodID, va_list);
  jchar     (*CallNonvirtualCharMethodA)(JNIEnv*, jobject, jclass,
            jmethodID, jvalue*);
  jshort    (*CallNonvirtualShortMethod)(JNIEnv*, jobject, jclass,
            jmethodID, ...);
  jshort    (*CallNonvirtualShortMethodV)(JNIEnv*, jobject, jclass,
            jmethodID, va_list);
  jshort    (*CallNonvirtualShortMethodA)(JNIEnv*, jobject, jclass,
            jmethodID, jvalue*);
  jint    (*CallNonvirtualIntMethod)(JNIEnv*, jobject, jclass,
            jmethodID, ...);
  jint    (*CallNonvirtualIntMethodV)(JNIEnv*, jobject, jclass,
            jmethodID, va_list);
  jint    (*CallNonvirtualIntMethodA)(JNIEnv*, jobject, jclass,
            jmethodID, jvalue*);
  jlong     (*CallNonvirtualLongMethod)(JNIEnv*, jobject, jclass,
            jmethodID, ...);
  jlong     (*CallNonvirtualLongMethodV)(JNIEnv*, jobject, jclass,
            jmethodID, va_list);
  jlong     (*CallNonvirtualLongMethodA)(JNIEnv*, jobject, jclass,
            jmethodID, jvalue*);
  jfloat    (*CallNonvirtualFloatMethod)(JNIEnv*, jobject, jclass,
            jmethodID, ...);
  jfloat    (*CallNonvirtualFloatMethodV)(JNIEnv*, jobject, jclass,
            jmethodID, va_list);
  jfloat    (*CallNonvirtualFloatMethodA)(JNIEnv*, jobject, jclass,
            jmethodID, jvalue*);
  jdouble   (*CallNonvirtualDoubleMethod)(JNIEnv*, jobject, jclass,
            jmethodID, ...);
  jdouble   (*CallNonvirtualDoubleMethodV)(JNIEnv*, jobject, jclass,
            jmethodID, va_list);
  jdouble   (*CallNonvirtualDoubleMethodA)(JNIEnv*, jobject, jclass,
            jmethodID, jvalue*);
  void    (*CallNonvirtualVoidMethod)(JNIEnv*, jobject, jclass,
            jmethodID, ...);
  void    (*CallNonvirtualVoidMethodV)(JNIEnv*, jobject, jclass,
            jmethodID, va_list);
  void    (*CallNonvirtualVoidMethodA)(JNIEnv*, jobject, jclass,
            jmethodID, jvalue*);

  jfieldID  (*GetFieldID)(JNIEnv*, jclass, const char*, const char*);

  jobject   (*GetObjectField)(JNIEnv*, jobject, jfieldID);
  jboolean  (*GetBooleanField)(JNIEnv*, jobject, jfieldID);
  jbyte     (*GetByteField)(JNIEnv*, jobject, jfieldID);
  jchar     (*GetCharField)(JNIEnv*, jobject, jfieldID);
  jshort    (*GetShortField)(JNIEnv*, jobject, jfieldID);
  jint    (*GetIntField)(JNIEnv*, jobject, jfieldID);
  jlong     (*GetLongField)(JNIEnv*, jobject, jfieldID);
  jfloat    (*GetFloatField)(JNIEnv*, jobject, jfieldID);
  jdouble   (*GetDoubleField)(JNIEnv*, jobject, jfieldID);

  void    (*SetObjectField)(JNIEnv*, jobject, jfieldID, jobject);
  void    (*SetBooleanField)(JNIEnv*, jobject, jfieldID, jboolean);
  void    (*SetByteField)(JNIEnv*, jobject, jfieldID, jbyte);
  void    (*SetCharField)(JNIEnv*, jobject, jfieldID, jchar);
  void    (*SetShortField)(JNIEnv*, jobject, jfieldID, jshort);
  void    (*SetIntField)(JNIEnv*, jobject, jfieldID, jint);
  void    (*SetLongField)(JNIEnv*, jobject, jfieldID, jlong);
  void    (*SetFloatField)(JNIEnv*, jobject, jfieldID, jfloat);
  void    (*SetDoubleField)(JNIEnv*, jobject, jfieldID, jdouble);

  jmethodID   (*GetStaticMethodID)(JNIEnv*, jclass, const char*, const char*);

  jobject   (*CallStaticObjectMethod)(JNIEnv*, jclass, jmethodID, ...);
  jobject   (*CallStaticObjectMethodV)(JNIEnv*, jclass, jmethodID, va_list);
  jobject   (*CallStaticObjectMethodA)(JNIEnv*, jclass, jmethodID, jvalue*);
  jboolean  (*CallStaticBooleanMethod)(JNIEnv*, jclass, jmethodID, ...);
  jboolean  (*CallStaticBooleanMethodV)(JNIEnv*, jclass, jmethodID,
            va_list);
  jboolean  (*CallStaticBooleanMethodA)(JNIEnv*, jclass, jmethodID,
            jvalue*);
  jbyte     (*CallStaticByteMethod)(JNIEnv*, jclass, jmethodID, ...);
  jbyte     (*CallStaticByteMethodV)(JNIEnv*, jclass, jmethodID, va_list);
  jbyte     (*CallStaticByteMethodA)(JNIEnv*, jclass, jmethodID, jvalue*);
  jchar     (*CallStaticCharMethod)(JNIEnv*, jclass, jmethodID, ...);
  jchar     (*CallStaticCharMethodV)(JNIEnv*, jclass, jmethodID, va_list);
  jchar     (*CallStaticCharMethodA)(JNIEnv*, jclass, jmethodID, jvalue*);
  jshort    (*CallStaticShortMethod)(JNIEnv*, jclass, jmethodID, ...);
  jshort    (*CallStaticShortMethodV)(JNIEnv*, jclass, jmethodID, va_list);
  jshort    (*CallStaticShortMethodA)(JNIEnv*, jclass, jmethodID, jvalue*);
  jint    (*CallStaticIntMethod)(JNIEnv*, jclass, jmethodID, ...);
  jint    (*CallStaticIntMethodV)(JNIEnv*, jclass, jmethodID, va_list);
  jint    (*CallStaticIntMethodA)(JNIEnv*, jclass, jmethodID, jvalue*);
  jlong     (*CallStaticLongMethod)(JNIEnv*, jclass, jmethodID, ...);
  jlong     (*CallStaticLongMethodV)(JNIEnv*, jclass, jmethodID, va_list);
  jlong     (*CallStaticLongMethodA)(JNIEnv*, jclass, jmethodID, jvalue*);
  jfloat    (*CallStaticFloatMethod)(JNIEnv*, jclass, jmethodID, ...);
  jfloat    (*CallStaticFloatMethodV)(JNIEnv*, jclass, jmethodID, va_list);
  jfloat    (*CallStaticFloatMethodA)(JNIEnv*, jclass, jmethodID, jvalue*);
  jdouble   (*CallStaticDoubleMethod)(JNIEnv*, jclass, jmethodID, ...);
  jdouble   (*CallStaticDoubleMethodV)(JNIEnv*, jclass, jmethodID, va_list);
  jdouble   (*CallStaticDoubleMethodA)(JNIEnv*, jclass, jmethodID, jvalue*);
  void    (*CallStaticVoidMethod)(JNIEnv*, jclass, jmethodID, ...);
  void    (*CallStaticVoidMethodV)(JNIEnv*, jclass, jmethodID, va_list);
  void    (*CallStaticVoidMethodA)(JNIEnv*, jclass, jmethodID, jvalue*);

  jfieldID  (*GetStaticFieldID)(JNIEnv*, jclass, const char*,
            const char*);

  jobject   (*GetStaticObjectField)(JNIEnv*, jclass, jfieldID);
  jboolean  (*GetStaticBooleanField)(JNIEnv*, jclass, jfieldID);
  jbyte     (*GetStaticByteField)(JNIEnv*, jclass, jfieldID);
  jchar     (*GetStaticCharField)(JNIEnv*, jclass, jfieldID);
  jshort    (*GetStaticShortField)(JNIEnv*, jclass, jfieldID);
  jint    (*GetStaticIntField)(JNIEnv*, jclass, jfieldID);
  jlong     (*GetStaticLongField)(JNIEnv*, jclass, jfieldID);
  jfloat    (*GetStaticFloatField)(JNIEnv*, jclass, jfieldID);
  jdouble   (*GetStaticDoubleField)(JNIEnv*, jclass, jfieldID);

  void    (*SetStaticObjectField)(JNIEnv*, jclass, jfieldID, jobject);
  void    (*SetStaticBooleanField)(JNIEnv*, jclass, jfieldID, jboolean);
  void    (*SetStaticByteField)(JNIEnv*, jclass, jfieldID, jbyte);
  void    (*SetStaticCharField)(JNIEnv*, jclass, jfieldID, jchar);
  void    (*SetStaticShortField)(JNIEnv*, jclass, jfieldID, jshort);
  void    (*SetStaticIntField)(JNIEnv*, jclass, jfieldID, jint);
  void    (*SetStaticLongField)(JNIEnv*, jclass, jfieldID, jlong);
  void    (*SetStaticFloatField)(JNIEnv*, jclass, jfieldID, jfloat);
  void    (*SetStaticDoubleField)(JNIEnv*, jclass, jfieldID, jdouble);

  jstring   (*NewString)(JNIEnv*, const jchar*, jsize);
  jsize     (*GetStringLength)(JNIEnv*, jstring);
  const jchar* (*GetStringChars)(JNIEnv*, jstring, jboolean*);
  void    (*ReleaseStringChars)(JNIEnv*, jstring, const jchar*);
  jstring   (*NewStringUTF)(JNIEnv*, const char*);
  jsize     (*GetStringUTFLength)(JNIEnv*, jstring);
  /* JNI spec says this returns const jbyte*, but that&#39;s inconsistent */
  const char* (*GetStringUTFChars)(JNIEnv*, jstring, jboolean*);
  void    (*ReleaseStringUTFChars)(JNIEnv*, jstring, const char*);
  jsize     (*GetArrayLength)(JNIEnv*, jarray);
  jobjectArray (*NewObjectArray)(JNIEnv*, jsize, jclass, jobject);
  jobject   (*GetObjectArrayElement)(JNIEnv*, jobjectArray, jsize);
  void    (*SetObjectArrayElement)(JNIEnv*, jobjectArray, jsize, jobject);

  jbooleanArray (*NewBooleanArray)(JNIEnv*, jsize);
  jbyteArray  (*NewByteArray)(JNIEnv*, jsize);
  jcharArray  (*NewCharArray)(JNIEnv*, jsize);
  jshortArray   (*NewShortArray)(JNIEnv*, jsize);
  jintArray   (*NewIntArray)(JNIEnv*, jsize);
  jlongArray  (*NewLongArray)(JNIEnv*, jsize);
  jfloatArray   (*NewFloatArray)(JNIEnv*, jsize);
  jdoubleArray  (*NewDoubleArray)(JNIEnv*, jsize);

  jboolean*   (*GetBooleanArrayElements)(JNIEnv*, jbooleanArray, jboolean*);
  jbyte*    (*GetByteArrayElements)(JNIEnv*, jbyteArray, jboolean*);
  jchar*    (*GetCharArrayElements)(JNIEnv*, jcharArray, jboolean*);
  jshort*   (*GetShortArrayElements)(JNIEnv*, jshortArray, jboolean*);
  jint*     (*GetIntArrayElements)(JNIEnv*, jintArray, jboolean*);
  jlong*    (*GetLongArrayElements)(JNIEnv*, jlongArray, jboolean*);
  jfloat*   (*GetFloatArrayElements)(JNIEnv*, jfloatArray, jboolean*);
  jdouble*  (*GetDoubleArrayElements)(JNIEnv*, jdoubleArray, jboolean*);

  void    (*ReleaseBooleanArrayElements)(JNIEnv*, jbooleanArray,
            jboolean*, jint);
  void    (*ReleaseByteArrayElements)(JNIEnv*, jbyteArray,
            jbyte*, jint);
  void    (*ReleaseCharArrayElements)(JNIEnv*, jcharArray,
            jchar*, jint);
  void    (*ReleaseShortArrayElements)(JNIEnv*, jshortArray,
            jshort*, jint);
  void    (*ReleaseIntArrayElements)(JNIEnv*, jintArray,
            jint*, jint);
  void    (*ReleaseLongArrayElements)(JNIEnv*, jlongArray,
            jlong*, jint);
  void    (*ReleaseFloatArrayElements)(JNIEnv*, jfloatArray,
            jfloat*, jint);
  void    (*ReleaseDoubleArrayElements)(JNIEnv*, jdoubleArray,
            jdouble*, jint);

  void    (*GetBooleanArrayRegion)(JNIEnv*, jbooleanArray,
            jsize, jsize, jboolean*);
  void    (*GetByteArrayRegion)(JNIEnv*, jbyteArray,
            jsize, jsize, jbyte*);
  void    (*GetCharArrayRegion)(JNIEnv*, jcharArray,
            jsize, jsize, jchar*);
  void    (*GetShortArrayRegion)(JNIEnv*, jshortArray,
            jsize, jsize, jshort*);
  void    (*GetIntArrayRegion)(JNIEnv*, jintArray,
            jsize, jsize, jint*);
  void    (*GetLongArrayRegion)(JNIEnv*, jlongArray,
            jsize, jsize, jlong*);
  void    (*GetFloatArrayRegion)(JNIEnv*, jfloatArray,
            jsize, jsize, jfloat*);
  void    (*GetDoubleArrayRegion)(JNIEnv*, jdoubleArray,
            jsize, jsize, jdouble*);

  /* spec shows these without const; some jni.h do, some don&#39;t */
  void    (*SetBooleanArrayRegion)(JNIEnv*, jbooleanArray,
            jsize, jsize, const jboolean*);
  void    (*SetByteArrayRegion)(JNIEnv*, jbyteArray,
            jsize, jsize, const jbyte*);
  void    (*SetCharArrayRegion)(JNIEnv*, jcharArray,
            jsize, jsize, const jchar*);
  void    (*SetShortArrayRegion)(JNIEnv*, jshortArray,
            jsize, jsize, const jshort*);
  void    (*SetIntArrayRegion)(JNIEnv*, jintArray,
            jsize, jsize, const jint*);
  void    (*SetLongArrayRegion)(JNIEnv*, jlongArray,
            jsize, jsize, const jlong*);
  void    (*SetFloatArrayRegion)(JNIEnv*, jfloatArray,
            jsize, jsize, const jfloat*);
  void    (*SetDoubleArrayRegion)(JNIEnv*, jdoubleArray,
            jsize, jsize, const jdouble*);

  jint    (*RegisterNatives)(JNIEnv*, jclass, const JNINativeMethod*,
            jint);
  jint    (*UnregisterNatives)(JNIEnv*, jclass);
  jint    (*MonitorEnter)(JNIEnv*, jobject);
  jint    (*MonitorExit)(JNIEnv*, jobject);
  jint    (*GetJavaVM)(JNIEnv*, JavaVM**);

  void    (*GetStringRegion)(JNIEnv*, jstring, jsize, jsize, jchar*);
  void    (*GetStringUTFRegion)(JNIEnv*, jstring, jsize, jsize, char*);

  void*     (*GetPrimitiveArrayCritical)(JNIEnv*, jarray, jboolean*);
  void    (*ReleasePrimitiveArrayCritical)(JNIEnv*, jarray, void*, jint);

  const jchar* (*GetStringCritical)(JNIEnv*, jstring, jboolean*);
  void    (*ReleaseStringCritical)(JNIEnv*, jstring, const jchar*);

  jweak     (*NewWeakGlobalRef)(JNIEnv*, jobject);
  void    (*DeleteWeakGlobalRef)(JNIEnv*, jweak);

  jboolean  (*ExceptionCheck)(JNIEnv*);

  jobject   (*NewDirectByteBuffer)(JNIEnv*, void*, jlong);
  void*     (*GetDirectBufferAddress)(JNIEnv*, jobject);
  jlong     (*GetDirectBufferCapacity)(JNIEnv*, jobject);

  /* added in JNI 1.6 */
  jobjectRefType (*GetObjectRefType)(JNIEnv*, jobject);
};

/*
 * C++ object wrapper.
 *
 * This is usually overlaid on a C struct whose first element is a
 * JNINativeInterface*.  We rely somewhat on compiler behavior.
 */
struct _JNIEnv {
  /* do not rename this; it does not seem to be entirely opaque */
  const struct JNINativeInterface* functions;

#if defined(__cplusplus)

  jint GetVersion()
  { return functions->GetVersion(this); }

  jclass DefineClass(const char *name, jobject loader, const jbyte* buf,
    jsize bufLen)
  { return functions->DefineClass(this, name, loader, buf, bufLen); }

  jclass FindClass(const char* name)
  { return functions->FindClass(this, name); }

  jmethodID FromReflectedMethod(jobject method)
  { return functions->FromReflectedMethod(this, method); }

  jfieldID FromReflectedField(jobject field)
  { return functions->FromReflectedField(this, field); }

  jobject ToReflectedMethod(jclass cls, jmethodID methodID, jboolean isStatic)
  { return functions->ToReflectedMethod(this, cls, methodID, isStatic); }

  jclass GetSuperclass(jclass clazz)
  { return functions->GetSuperclass(this, clazz); }

  jboolean IsAssignableFrom(jclass clazz1, jclass clazz2)
  { return functions->IsAssignableFrom(this, clazz1, clazz2); }

  jobject ToReflectedField(jclass cls, jfieldID fieldID, jboolean isStatic)
  { return functions->ToReflectedField(this, cls, fieldID, isStatic); }

  jint Throw(jthrowable obj)
  { return functions->Throw(this, obj); }

  jint ThrowNew(jclass clazz, const char* message)
  { return functions->ThrowNew(this, clazz, message); }

  jthrowable ExceptionOccurred()
  { return functions->ExceptionOccurred(this); }

  void ExceptionDescribe()
  { functions->ExceptionDescribe(this); }

  void ExceptionClear()
  { functions->ExceptionClear(this); }

  void FatalError(const char* msg)
  { functions->FatalError(this, msg); }

  jint PushLocalFrame(jint capacity)
  { return functions->PushLocalFrame(this, capacity); }

  jobject PopLocalFrame(jobject result)
  { return functions->PopLocalFrame(this, result); }

  jobject NewGlobalRef(jobject obj)
  { return functions->NewGlobalRef(this, obj); }

  void DeleteGlobalRef(jobject globalRef)
  { functions->DeleteGlobalRef(this, globalRef); }

  void DeleteLocalRef(jobject localRef)
  { functions->DeleteLocalRef(this, localRef); }

  jboolean IsSameObject(jobject ref1, jobject ref2)
  { return functions->IsSameObject(this, ref1, ref2); }

  jobject NewLocalRef(jobject ref)
  { return functions->NewLocalRef(this, ref); }

  jint EnsureLocalCapacity(jint capacity)
  { return functions->EnsureLocalCapacity(this, capacity); }

  jobject AllocObject(jclass clazz)
  { return functions->AllocObject(this, clazz); }

  jobject NewObject(jclass clazz, jmethodID methodID, ...)
  {
    va_list args;
    va_start(args, methodID);
    jobject result = functions->NewObjectV(this, clazz, methodID, args);
    va_end(args);
    return result;
  }

  jobject NewObjectV(jclass clazz, jmethodID methodID, va_list args)
  { return functions->NewObjectV(this, clazz, methodID, args); }

  jobject NewObjectA(jclass clazz, jmethodID methodID, jvalue* args)
  { return functions->NewObjectA(this, clazz, methodID, args); }

  jclass GetObjectClass(jobject obj)
  { return functions->GetObjectClass(this, obj); }

  jboolean IsInstanceOf(jobject obj, jclass clazz)
  { return functions->IsInstanceOf(this, obj, clazz); }

  jmethodID GetMethodID(jclass clazz, const char* name, const char* sig)
  { return functions->GetMethodID(this, clazz, name, sig); }

#define CALL_TYPE_METHOD(_jtype, _jname)                  \
  _jtype Call##_jname##Method(jobject obj, jmethodID methodID, ...)     \
  {                                     \
    _jtype result;                            \
    va_list args;                             \
    va_start(args, methodID);                       \
    result = functions->Call##_jname##MethodV(this, obj, methodID,    \
          args);                          \
    va_end(args);                             \
    return result;                            \
  }
#define CALL_TYPE_METHODV(_jtype, _jname)                   \
  _jtype Call##_jname##MethodV(jobject obj, jmethodID methodID,       \
    va_list args)                             \
  { return functions->Call##_jname##MethodV(this, obj, methodID, args); }
#define CALL_TYPE_METHODA(_jtype, _jname)                   \
  _jtype Call##_jname##MethodA(jobject obj, jmethodID methodID,       \
    jvalue* args)                             \
  { return functions->Call##_jname##MethodA(this, obj, methodID, args); }

#define CALL_TYPE(_jtype, _jname)                       \
  CALL_TYPE_METHOD(_jtype, _jname)                    \
  CALL_TYPE_METHODV(_jtype, _jname)                     \
  CALL_TYPE_METHODA(_jtype, _jname)

  CALL_TYPE(jobject, Object)
  CALL_TYPE(jboolean, Boolean)
  CALL_TYPE(jbyte, Byte)
  CALL_TYPE(jchar, Char)
  CALL_TYPE(jshort, Short)
  CALL_TYPE(jint, Int)
  CALL_TYPE(jlong, Long)
  CALL_TYPE(jfloat, Float)
  CALL_TYPE(jdouble, Double)

  void CallVoidMethod(jobject obj, jmethodID methodID, ...)
  {
    va_list args;
    va_start(args, methodID);
    functions->CallVoidMethodV(this, obj, methodID, args);
    va_end(args);
  }
  void CallVoidMethodV(jobject obj, jmethodID methodID, va_list args)
  { functions->CallVoidMethodV(this, obj, methodID, args); }
  void CallVoidMethodA(jobject obj, jmethodID methodID, jvalue* args)
  { functions->CallVoidMethodA(this, obj, methodID, args); }

#define CALL_NONVIRT_TYPE_METHOD(_jtype, _jname)              \
  _jtype CallNonvirtual##_jname##Method(jobject obj, jclass clazz,    \
    jmethodID methodID, ...)                      \
  {                                     \
    _jtype result;                            \
    va_list args;                             \
    va_start(args, methodID);                       \
    result = functions->CallNonvirtual##_jname##MethodV(this, obj,    \
          clazz, methodID, args);                 \
    va_end(args);                             \
    return result;                            \
  }
#define CALL_NONVIRT_TYPE_METHODV(_jtype, _jname)               \
  _jtype CallNonvirtual##_jname##MethodV(jobject obj, jclass clazz,     \
    jmethodID methodID, va_list args)                   \
  { return functions->CallNonvirtual##_jname##MethodV(this, obj, clazz,   \
    methodID, args); }
#define CALL_NONVIRT_TYPE_METHODA(_jtype, _jname)               \
  _jtype CallNonvirtual##_jname##MethodA(jobject obj, jclass clazz,     \
    jmethodID methodID, jvalue* args)                   \
  { return functions->CallNonvirtual##_jname##MethodA(this, obj, clazz,   \
    methodID, args); }

#define CALL_NONVIRT_TYPE(_jtype, _jname)                   \
  CALL_NONVIRT_TYPE_METHOD(_jtype, _jname)                \
  CALL_NONVIRT_TYPE_METHODV(_jtype, _jname)                 \
  CALL_NONVIRT_TYPE_METHODA(_jtype, _jname)

  CALL_NONVIRT_TYPE(jobject, Object)
  CALL_NONVIRT_TYPE(jboolean, Boolean)
  CALL_NONVIRT_TYPE(jbyte, Byte)
  CALL_NONVIRT_TYPE(jchar, Char)
  CALL_NONVIRT_TYPE(jshort, Short)
  CALL_NONVIRT_TYPE(jint, Int)
  CALL_NONVIRT_TYPE(jlong, Long)
  CALL_NONVIRT_TYPE(jfloat, Float)
  CALL_NONVIRT_TYPE(jdouble, Double)

  void CallNonvirtualVoidMethod(jobject obj, jclass clazz,
    jmethodID methodID, ...)
  {
    va_list args;
    va_start(args, methodID);
    functions->CallNonvirtualVoidMethodV(this, obj, clazz, methodID, args);
    va_end(args);
  }
  void CallNonvirtualVoidMethodV(jobject obj, jclass clazz,
    jmethodID methodID, va_list args)
  { functions->CallNonvirtualVoidMethodV(this, obj, clazz, methodID, args); }
  void CallNonvirtualVoidMethodA(jobject obj, jclass clazz,
    jmethodID methodID, jvalue* args)
  { functions->CallNonvirtualVoidMethodA(this, obj, clazz, methodID, args); }

  jfieldID GetFieldID(jclass clazz, const char* name, const char* sig)
  { return functions->GetFieldID(this, clazz, name, sig); }

  jobject GetObjectField(jobject obj, jfieldID fieldID)
  { return functions->GetObjectField(this, obj, fieldID); }
  jboolean GetBooleanField(jobject obj, jfieldID fieldID)
  { return functions->GetBooleanField(this, obj, fieldID); }
  jbyte GetByteField(jobject obj, jfieldID fieldID)
  { return functions->GetByteField(this, obj, fieldID); }
  jchar GetCharField(jobject obj, jfieldID fieldID)
  { return functions->GetCharField(this, obj, fieldID); }
  jshort GetShortField(jobject obj, jfieldID fieldID)
  { return functions->GetShortField(this, obj, fieldID); }
  jint GetIntField(jobject obj, jfieldID fieldID)
  { return functions->GetIntField(this, obj, fieldID); }
  jlong GetLongField(jobject obj, jfieldID fieldID)
  { return functions->GetLongField(this, obj, fieldID); }
  jfloat GetFloatField(jobject obj, jfieldID fieldID)
  { return functions->GetFloatField(this, obj, fieldID); }
  jdouble GetDoubleField(jobject obj, jfieldID fieldID)
  { return functions->GetDoubleField(this, obj, fieldID); }

  void SetObjectField(jobject obj, jfieldID fieldID, jobject value)
  { functions->SetObjectField(this, obj, fieldID, value); }
  void SetBooleanField(jobject obj, jfieldID fieldID, jboolean value)
  { functions->SetBooleanField(this, obj, fieldID, value); }
  void SetByteField(jobject obj, jfieldID fieldID, jbyte value)
  { functions->SetByteField(this, obj, fieldID, value); }
  void SetCharField(jobject obj, jfieldID fieldID, jchar value)
  { functions->SetCharField(this, obj, fieldID, value); }
  void SetShortField(jobject obj, jfieldID fieldID, jshort value)
  { functions->SetShortField(this, obj, fieldID, value); }
  void SetIntField(jobject obj, jfieldID fieldID, jint value)
  { functions->SetIntField(this, obj, fieldID, value); }
  void SetLongField(jobject obj, jfieldID fieldID, jlong value)
  { functions->SetLongField(this, obj, fieldID, value); }
  void SetFloatField(jobject obj, jfieldID fieldID, jfloat value)
  { functions->SetFloatField(this, obj, fieldID, value); }
  void SetDoubleField(jobject obj, jfieldID fieldID, jdouble value)
  { functions->SetDoubleField(this, obj, fieldID, value); }

  jmethodID GetStaticMethodID(jclass clazz, const char* name, const char* sig)
  { return functions->GetStaticMethodID(this, clazz, name, sig); }

#define CALL_STATIC_TYPE_METHOD(_jtype, _jname)               \
  _jtype CallStatic##_jname##Method(jclass clazz, jmethodID methodID,   \
    ...)                                \
  {                                     \
    _jtype result;                            \
    va_list args;                             \
    va_start(args, methodID);                       \
    result = functions->CallStatic##_jname##MethodV(this, clazz,    \
          methodID, args);                    \
    va_end(args);                             \
    return result;                            \
  }
#define CALL_STATIC_TYPE_METHODV(_jtype, _jname)              \
  _jtype CallStatic##_jname##MethodV(jclass clazz, jmethodID methodID,  \
    va_list args)                             \
  { return functions->CallStatic##_jname##MethodV(this, clazz, methodID,  \
    args); }
#define CALL_STATIC_TYPE_METHODA(_jtype, _jname)              \
  _jtype CallStatic##_jname##MethodA(jclass clazz, jmethodID methodID,  \
    jvalue* args)                             \
  { return functions->CallStatic##_jname##MethodA(this, clazz, methodID,  \
    args); }

#define CALL_STATIC_TYPE(_jtype, _jname)                  \
  CALL_STATIC_TYPE_METHOD(_jtype, _jname)                 \
  CALL_STATIC_TYPE_METHODV(_jtype, _jname)                \
  CALL_STATIC_TYPE_METHODA(_jtype, _jname)

  CALL_STATIC_TYPE(jobject, Object)
  CALL_STATIC_TYPE(jboolean, Boolean)
  CALL_STATIC_TYPE(jbyte, Byte)
  CALL_STATIC_TYPE(jchar, Char)
  CALL_STATIC_TYPE(jshort, Short)
  CALL_STATIC_TYPE(jint, Int)
  CALL_STATIC_TYPE(jlong, Long)
  CALL_STATIC_TYPE(jfloat, Float)
  CALL_STATIC_TYPE(jdouble, Double)

  void CallStaticVoidMethod(jclass clazz, jmethodID methodID, ...)
  {
    va_list args;
    va_start(args, methodID);
    functions->CallStaticVoidMethodV(this, clazz, methodID, args);
    va_end(args);
  }
  void CallStaticVoidMethodV(jclass clazz, jmethodID methodID, va_list args)
  { functions->CallStaticVoidMethodV(this, clazz, methodID, args); }
  void CallStaticVoidMethodA(jclass clazz, jmethodID methodID, jvalue* args)
  { functions->CallStaticVoidMethodA(this, clazz, methodID, args); }

  jfieldID GetStaticFieldID(jclass clazz, const char* name, const char* sig)
  { return functions->GetStaticFieldID(this, clazz, name, sig); }

  jobject GetStaticObjectField(jclass clazz, jfieldID fieldID)
  { return functions->GetStaticObjectField(this, clazz, fieldID); }
  jboolean GetStaticBooleanField(jclass clazz, jfieldID fieldID)
  { return functions->GetStaticBooleanField(this, clazz, fieldID); }
  jbyte GetStaticByteField(jclass clazz, jfieldID fieldID)
  { return functions->GetStaticByteField(this, clazz, fieldID); }
  jchar GetStaticCharField(jclass clazz, jfieldID fieldID)
  { return functions->GetStaticCharField(this, clazz, fieldID); }
  jshort GetStaticShortField(jclass clazz, jfieldID fieldID)
  { return functions->GetStaticShortField(this, clazz, fieldID); }
  jint GetStaticIntField(jclass clazz, jfieldID fieldID)
  { return functions->GetStaticIntField(this, clazz, fieldID); }
  jlong GetStaticLongField(jclass clazz, jfieldID fieldID)
  { return functions->GetStaticLongField(this, clazz, fieldID); }
  jfloat GetStaticFloatField(jclass clazz, jfieldID fieldID)
  { return functions->GetStaticFloatField(this, clazz, fieldID); }
  jdouble GetStaticDoubleField(jclass clazz, jfieldID fieldID)
  { return functions->GetStaticDoubleField(this, clazz, fieldID); }

  void SetStaticObjectField(jclass clazz, jfieldID fieldID, jobject value)
  { functions->SetStaticObjectField(this, clazz, fieldID, value); }
  void SetStaticBooleanField(jclass clazz, jfieldID fieldID, jboolean value)
  { functions->SetStaticBooleanField(this, clazz, fieldID, value); }
  void SetStaticByteField(jclass clazz, jfieldID fieldID, jbyte value)
  { functions->SetStaticByteField(this, clazz, fieldID, value); }
  void SetStaticCharField(jclass clazz, jfieldID fieldID, jchar value)
  { functions->SetStaticCharField(this, clazz, fieldID, value); }
  void SetStaticShortField(jclass clazz, jfieldID fieldID, jshort value)
  { functions->SetStaticShortField(this, clazz, fieldID, value); }
  void SetStaticIntField(jclass clazz, jfieldID fieldID, jint value)
  { functions->SetStaticIntField(this, clazz, fieldID, value); }
  void SetStaticLongField(jclass clazz, jfieldID fieldID, jlong value)
  { functions->SetStaticLongField(this, clazz, fieldID, value); }
  void SetStaticFloatField(jclass clazz, jfieldID fieldID, jfloat value)
  { functions->SetStaticFloatField(this, clazz, fieldID, value); }
  void SetStaticDoubleField(jclass clazz, jfieldID fieldID, jdouble value)
  { functions->SetStaticDoubleField(this, clazz, fieldID, value); }

  jstring NewString(const jchar* unicodeChars, jsize len)
  { return functions->NewString(this, unicodeChars, len); }

  jsize GetStringLength(jstring string)
  { return functions->GetStringLength(this, string); }

  const jchar* GetStringChars(jstring string, jboolean* isCopy)
  { return functions->GetStringChars(this, string, isCopy); }

  void ReleaseStringChars(jstring string, const jchar* chars)
  { functions->ReleaseStringChars(this, string, chars); }

  jstring NewStringUTF(const char* bytes)
  { return functions->NewStringUTF(this, bytes); }

  jsize GetStringUTFLength(jstring string)
  { return functions->GetStringUTFLength(this, string); }

  const char* GetStringUTFChars(jstring string, jboolean* isCopy)
  { return functions->GetStringUTFChars(this, string, isCopy); }

  void ReleaseStringUTFChars(jstring string, const char* utf)
  { functions->ReleaseStringUTFChars(this, string, utf); }

  jsize GetArrayLength(jarray array)
  { return functions->GetArrayLength(this, array); }

  jobjectArray NewObjectArray(jsize length, jclass elementClass,
    jobject initialElement)
  { return functions->NewObjectArray(this, length, elementClass,
    initialElement); }

  jobject GetObjectArrayElement(jobjectArray array, jsize index)
  { return functions->GetObjectArrayElement(this, array, index); }

  void SetObjectArrayElement(jobjectArray array, jsize index, jobject value)
  { functions->SetObjectArrayElement(this, array, index, value); }

  jbooleanArray NewBooleanArray(jsize length)
  { return functions->NewBooleanArray(this, length); }
  jbyteArray NewByteArray(jsize length)
  { return functions->NewByteArray(this, length); }
  jcharArray NewCharArray(jsize length)
  { return functions->NewCharArray(this, length); }
  jshortArray NewShortArray(jsize length)
  { return functions->NewShortArray(this, length); }
  jintArray NewIntArray(jsize length)
  { return functions->NewIntArray(this, length); }
  jlongArray NewLongArray(jsize length)
  { return functions->NewLongArray(this, length); }
  jfloatArray NewFloatArray(jsize length)
  { return functions->NewFloatArray(this, length); }
  jdoubleArray NewDoubleArray(jsize length)
  { return functions->NewDoubleArray(this, length); }

  jboolean* GetBooleanArrayElements(jbooleanArray array, jboolean* isCopy)
  { return functions->GetBooleanArrayElements(this, array, isCopy); }
  jbyte* GetByteArrayElements(jbyteArray array, jboolean* isCopy)
  { return functions->GetByteArrayElements(this, array, isCopy); }
  jchar* GetCharArrayElements(jcharArray array, jboolean* isCopy)
  { return functions->GetCharArrayElements(this, array, isCopy); }
  jshort* GetShortArrayElements(jshortArray array, jboolean* isCopy)
  { return functions->GetShortArrayElements(this, array, isCopy); }
  jint* GetIntArrayElements(jintArray array, jboolean* isCopy)
  { return functions->GetIntArrayElements(this, array, isCopy); }
  jlong* GetLongArrayElements(jlongArray array, jboolean* isCopy)
  { return functions->GetLongArrayElements(this, array, isCopy); }
  jfloat* GetFloatArrayElements(jfloatArray array, jboolean* isCopy)
  { return functions->GetFloatArrayElements(this, array, isCopy); }
  jdouble* GetDoubleArrayElements(jdoubleArray array, jboolean* isCopy)
  { return functions->GetDoubleArrayElements(this, array, isCopy); }

  void ReleaseBooleanArrayElements(jbooleanArray array, jboolean* elems,
    jint mode)
  { functions->ReleaseBooleanArrayElements(this, array, elems, mode); }
  void ReleaseByteArrayElements(jbyteArray array, jbyte* elems,
    jint mode)
  { functions->ReleaseByteArrayElements(this, array, elems, mode); }
  void ReleaseCharArrayElements(jcharArray array, jchar* elems,
    jint mode)
  { functions->ReleaseCharArrayElements(this, array, elems, mode); }
  void ReleaseShortArrayElements(jshortArray array, jshort* elems,
    jint mode)
  { functions->ReleaseShortArrayElements(this, array, elems, mode); }
  void ReleaseIntArrayElements(jintArray array, jint* elems,
    jint mode)
  { functions->ReleaseIntArrayElements(this, array, elems, mode); }
  void ReleaseLongArrayElements(jlongArray array, jlong* elems,
    jint mode)
  { functions->ReleaseLongArrayElements(this, array, elems, mode); }
  void ReleaseFloatArrayElements(jfloatArray array, jfloat* elems,
    jint mode)
  { functions->ReleaseFloatArrayElements(this, array, elems, mode); }
  void ReleaseDoubleArrayElements(jdoubleArray array, jdouble* elems,
    jint mode)
  { functions->ReleaseDoubleArrayElements(this, array, elems, mode); }

  void GetBooleanArrayRegion(jbooleanArray array, jsize start, jsize len,
    jboolean* buf)
  { functions->GetBooleanArrayRegion(this, array, start, len, buf); }
  void GetByteArrayRegion(jbyteArray array, jsize start, jsize len,
    jbyte* buf)
  { functions->GetByteArrayRegion(this, array, start, len, buf); }
  void GetCharArrayRegion(jcharArray array, jsize start, jsize len,
    jchar* buf)
  { functions->GetCharArrayRegion(this, array, start, len, buf); }
  void GetShortArrayRegion(jshortArray array, jsize start, jsize len,
    jshort* buf)
  { functions->GetShortArrayRegion(this, array, start, len, buf); }
  void GetIntArrayRegion(jintArray array, jsize start, jsize len,
    jint* buf)
  { functions->GetIntArrayRegion(this, array, start, len, buf); }
  void GetLongArrayRegion(jlongArray array, jsize start, jsize len,
    jlong* buf)
  { functions->GetLongArrayRegion(this, array, start, len, buf); }
  void GetFloatArrayRegion(jfloatArray array, jsize start, jsize len,
    jfloat* buf)
  { functions->GetFloatArrayRegion(this, array, start, len, buf); }
  void GetDoubleArrayRegion(jdoubleArray array, jsize start, jsize len,
    jdouble* buf)
  { functions->GetDoubleArrayRegion(this, array, start, len, buf); }

  void SetBooleanArrayRegion(jbooleanArray array, jsize start, jsize len,
    const jboolean* buf)
  { functions->SetBooleanArrayRegion(this, array, start, len, buf); }
  void SetByteArrayRegion(jbyteArray array, jsize start, jsize len,
    const jbyte* buf)
  { functions->SetByteArrayRegion(this, array, start, len, buf); }
  void SetCharArrayRegion(jcharArray array, jsize start, jsize len,
    const jchar* buf)
  { functions->SetCharArrayRegion(this, array, start, len, buf); }
  void SetShortArrayRegion(jshortArray array, jsize start, jsize len,
    const jshort* buf)
  { functions->SetShortArrayRegion(this, array, start, len, buf); }
  void SetIntArrayRegion(jintArray array, jsize start, jsize len,
    const jint* buf)
  { functions->SetIntArrayRegion(this, array, start, len, buf); }
  void SetLongArrayRegion(jlongArray array, jsize start, jsize len,
    const jlong* buf)
  { functions->SetLongArrayRegion(this, array, start, len, buf); }
  void SetFloatArrayRegion(jfloatArray array, jsize start, jsize len,
    const jfloat* buf)
  { functions->SetFloatArrayRegion(this, array, start, len, buf); }
  void SetDoubleArrayRegion(jdoubleArray array, jsize start, jsize len,
    const jdouble* buf)
  { functions->SetDoubleArrayRegion(this, array, start, len, buf); }

  jint RegisterNatives(jclass clazz, const JNINativeMethod* methods,
    jint nMethods)
  { return functions->RegisterNatives(this, clazz, methods, nMethods); }

  jint UnregisterNatives(jclass clazz)
  { return functions->UnregisterNatives(this, clazz); }

  jint MonitorEnter(jobject obj)
  { return functions->MonitorEnter(this, obj); }

  jint MonitorExit(jobject obj)
  { return functions->MonitorExit(this, obj); }

  jint GetJavaVM(JavaVM** vm)
  { return functions->GetJavaVM(this, vm); }

  void GetStringRegion(jstring str, jsize start, jsize len, jchar* buf)
  { functions->GetStringRegion(this, str, start, len, buf); }

  void GetStringUTFRegion(jstring str, jsize start, jsize len, char* buf)
  { return functions->GetStringUTFRegion(this, str, start, len, buf); }

  void* GetPrimitiveArrayCritical(jarray array, jboolean* isCopy)
  { return functions->GetPrimitiveArrayCritical(this, array, isCopy); }

  void ReleasePrimitiveArrayCritical(jarray array, void* carray, jint mode)
  { functions->ReleasePrimitiveArrayCritical(this, array, carray, mode); }

  const jchar* GetStringCritical(jstring string, jboolean* isCopy)
  { return functions->GetStringCritical(this, string, isCopy); }

  void ReleaseStringCritical(jstring string, const jchar* carray)
  { functions->ReleaseStringCritical(this, string, carray); }

  jweak NewWeakGlobalRef(jobject obj)
  { return functions->NewWeakGlobalRef(this, obj); }

  void DeleteWeakGlobalRef(jweak obj)
  { functions->DeleteWeakGlobalRef(this, obj); }

  jboolean ExceptionCheck()
  { return functions->ExceptionCheck(this); }

  jobject NewDirectByteBuffer(void* address, jlong capacity)
  { return functions->NewDirectByteBuffer(this, address, capacity); }

  void* GetDirectBufferAddress(jobject buf)
  { return functions->GetDirectBufferAddress(this, buf); }

  jlong GetDirectBufferCapacity(jobject buf)
  { return functions->GetDirectBufferCapacity(this, buf); }

  /* added in JNI 1.6 */
  jobjectRefType GetObjectRefType(jobject obj)
  { return functions->GetObjectRefType(this, obj); }
#endif /*__cplusplus*/
};


/*
 * JNI invocation interface.
 */
struct JNIInvokeInterface {
  void*     reserved0;
  void*     reserved1;
  void*     reserved2;

  jint    (*DestroyJavaVM)(JavaVM*);
  jint    (*AttachCurrentThread)(JavaVM*, JNIEnv**, void*);
  jint    (*DetachCurrentThread)(JavaVM*);
  jint    (*GetEnv)(JavaVM*, void**, jint);
  jint    (*AttachCurrentThreadAsDaemon)(JavaVM*, JNIEnv**, void*);
};

/*
 * C++ version.
 */
struct _JavaVM {
  const struct JNIInvokeInterface* functions;

#if defined(__cplusplus)
  jint DestroyJavaVM()
  { return functions->DestroyJavaVM(this); }
  jint AttachCurrentThread(JNIEnv** p_env, void* thr_args)
  { return functions->AttachCurrentThread(this, p_env, thr_args); }
  jint DetachCurrentThread()
  { return functions->DetachCurrentThread(this); }
  jint GetEnv(void** env, jint version)
  { return functions->GetEnv(this, env, version); }
  jint AttachCurrentThreadAsDaemon(JNIEnv** p_env, void* thr_args)
  { return functions->AttachCurrentThreadAsDaemon(this, p_env, thr_args); }
#endif /*__cplusplus*/
};

struct JavaVMAttachArgs {
  jint    version;  /* must be >= JNI_VERSION_1_2 */
  const char* name;     /* NULL or name of thread as modified UTF-8 str */
  jobject   group;    /* global ref of a ThreadGroup object, or NULL */
};
typedef struct JavaVMAttachArgs JavaVMAttachArgs;

/*
 * JNI 1.2+ initialization.  (As of 1.6, the pre-1.2 structures are no
 * longer supported.)
 */
typedef struct JavaVMOption {
  const char* optionString;
  void*     extraInfo;
} JavaVMOption;

typedef struct JavaVMInitArgs {
  jint    version;  /* use JNI_VERSION_1_2 or later */

  jint    nOptions;
  JavaVMOption* options;
  jboolean  ignoreUnrecognized;
} JavaVMInitArgs;

#ifdef __cplusplus
extern "C" {
#endif
/*
 * VM initialization functions.
 *
 * Note these are the only symbols exported for JNI by the VM.
 */
#if 0  /* In practice, these are not exported by the NDK so don&#39;t declare them */
jint JNI_GetDefaultJavaVMInitArgs(void*);
jint JNI_CreateJavaVM(JavaVM**, JNIEnv**, void*);
jint JNI_GetCreatedJavaVMs(JavaVM**, jsize, jsize*);
#endif

#define JNIIMPORT
#define JNIEXPORT  __attribute__ ((visibility ("default")))
#define JNICALL

/*
 * Prototypes for functions exported by loadable shared libs.  These are
 * called by JNI, not provided by JNI.
 */
JNIEXPORT jint JNI_OnLoad(JavaVM* vm, void* reserved);
JNIEXPORT void JNI_OnUnload(JavaVM* vm, void* reserved);

#ifdef __cplusplus
}
#endif


/*
 * Manifest constants.
 */
#define JNI_FALSE   0
#define JNI_TRUE  1

#define JNI_VERSION_1_1 0x00010001
#define JNI_VERSION_1_2 0x00010002
#define JNI_VERSION_1_4 0x00010004
#define JNI_VERSION_1_6 0x00010006

#define JNI_OK      (0)     /* no error */
#define JNI_ERR     (-1)    /* generic error */
#define JNI_EDETACHED   (-2)    /* thread detached from the VM */
#define JNI_EVERSION  (-3)    /* JNI version error */

#define JNI_COMMIT    1       /* copy content, do not free buffer */
#define JNI_ABORT     2       /* free buffer w/o copying back */

#endif  /* JNI_H_ */

官方文档:http://docs.oracle.com/javase/6/docs/technotes/guides/jni/spec/jniTOC.html

JNIEnv不能在任意线程中使用。必须是原本就是Java线程(Java代码通过JNI调用native代码时,发起调用的那个肯定是Java线程),或者是让已有的native线程通过JNI来attach到Java环境。 你的每个“C++线程”里都应该要调用AttachCurrentThread()来确保它确实attach到Java环境里了。

jint JNI_CreateJavaVM(JavaVM **p_vm, JNIEnv **p_env, void *vm_args);  

这个函数会通过p_env来返回适合这个通过JNI创建JVM实例的线程使用的JNIEnv。所以你会在各种例子里面看到人家这样写:

JavaVM* jvm = NULL;  
JNIEnv* env = NULL;  
void* vm_args = ...;  
jint res = JNI_CreateJavaVM(&jvm, &env, vm_args);  
if (res < 0) {  
  // Create JVM failed ...  
}  

这样调用完之后env就指向了一个可用的JNIEnv。

jint AttachCurrentThread(JavaVM *vm, JNIEnv **p_env, void *thr_args);  

同样通过p_env来返回。这是把当前线程(一个已有的native线程)attach到Java环境里。同一个线程反复调用attach不会真的反复attach。

jint AttachCurrentThreadAsDaemon(JavaVM* vm, void** penv, void* args);  

同上。只是attach的时候指定作为daemon线程来attach。

jint GetEnv(JavaVM *vm, void **env, jint version);  

通过JavaVM获取当前线程适用的JNIEnv,通过env返回。如果当前线程没有attach到Java环境里,那么env会被置为NULL,而GetEnv的返回值会是JNI_EDETACHED。

[copy from http://hllvm.group.iteye.com/group/topic/33519]