JNI (Java Native Interface)

1. JNI とは？
2. JNI サンプル
   1. native を含む java のプログラムを作り、コンパイルします
   2. クラスファイルから c プログラム用のヘッダファイルを作ります
   3. native 関数を含む c プログラムを作成、コンパイル、共有ライブラリを作ります
   4. java プログラムを実行します
3. JNIEnv 構造体

JNI とは？

Java でアプリケーション全体を記述できる一方で、 Java だけではアプリケーションのニーズを満たせない状況もあります。 Java でアプリケーション全体を記述できない場合、プログラマは JNI を使用して、 Java ネイティブメソッドを記述することにより、 このような状況に対処できます。

以下に、Java ネイティブメソッドを使用する必要のある場合をいくつか示します。

• 標準 Java クラスライブラリが、 アプリケーションに必要なプラットフォーム依存機能をサポートしない場合
• 他の言語で記述されたライブラリをすでに持っており、 そのライブラリから JNI を経由して Java コードにアクセスさせる場合
• 一部のタイムクリティカルなコードをアセンブリなどの低レベル言語で 実装する必要がある場合

JNI を介して、プログラムにネイティブメソッドを使用することにより、 以下のことが可能になります。

• Java オブジェクト (配列と文字列を含む) の生成、検査、更新
• Java メソッドの呼び出し
• 例外のキャッチおよびスロー
• クラスのロード、およびクラス情報の取得
• 実行時の型チェック

また、呼び出し API とともに JNI を使用することにより、 任意のネイティブアプリケーションによる Java VM の埋め込みが可能になります。 これにより、プログラマは VM ソースコードにリンクしなくても、 既存のアプリケーションを Java 対応にできます。

JNI のサンプル

c 言語を使った JNI のプログラムを作る手順は、以下のとおりです。

1. native を含む java のプログラムを作り、コンパイルします。(tstJNI.java)
2. クラスファイルから c プログラム用のヘッダファイルを作ります。
3. native 関数を含む c プログラムを作成し、コンパイルし、共有ライブラリを作ります。(tstJNI.c)
4. 環境変数 LD_LIBRARY_PATH に共有ライブラリのパスを追加します。
5. java プログラムを実行します。

> javac tstJNI.java                                                     .. 1
> javah -jni tstJNI                                                     .. 2
> cc -I/usr/java1.2/include -I/usr/java1.2/include/solaris -c tstJNI.c  .. 3
> cc -G tstJNI.o -o libtstJNI.so
> setenv LD_LIBRARY_PATH .:${LD_LIBRARY_PATH}                           .. 4
> java tstJNI                                                           .. 5

native を含む java のプログラムを作り、コンパイルします

native メソッド canRead() は、ファイル名を引数で受け取り、 そのファイルが読めるかを判定する c のプログラムです。

canRead() を含む共用ライブラリ libtstJNI.so を使用する前に System.loadLibrary() でロードしなければなりません。

import java.io.*;

public class tstJNI {
   static final String  fname="tstJNI.java";
   private native boolean canRead(String s);

   public static void main(String argv[]) {
      tstJNI    tt = new tstJNI();

      System.loadLibrary("tstJNI");
      if (tt.canRead(fname))  {
         try {
           FileInputStream f = new FileInputStream(fname);
           int b;

           while((b=f.read()) != -1) {
              System.out.print((char) b);
           }
           System.out.flush();
         } catch (IOException e) {  e.printStackTrace(); }
      }
      else System.out.println(fname +" can't open");
   }
}

クラスファイルから c プログラム用のヘッダファイルを作ります

/* DO NOT EDIT THIS FILE - it is machine generated */
#include 
/* Header for class tstJNI */

#ifndef _Included_tstJNI
#define _Included_tstJNI
#ifdef __cplusplus
extern "C" {
#endif
/*
 * Class:     tstJNI
 * Method:    canRead
 * Signature: (Ljava/lang/String;)Z
 */
JNIEXPORT jboolean JNICALL Java_tstJNI_canRead
  (JNIEnv *, jobject, jstring);

#ifdef __cplusplus
}
#endif
#endif

native 関数を含む c プログラムを作成、コンパイル、共有ライブラリを作ります

まず、javah で作成したヘッダファイルをインクルードする必要があります。

JNIEnv には java の環境情報がすべて含まれており、 ここから変換関数などを呼び出すことができます。

GetStringUTFChars は、java の String を c の char * に変換する関数です。

#include "tstJNI.h" 
#include <unistd.h>

JNIEXPORT jboolean JNICALL Java_tstJNI_canRead (JNIEnv *e,jobject o,jstring s){
   jboolean   ret=JNI_FALSE;
   char       *cp;
   int        iret;

/* convert from Java String to char*         */
   cp = (*e)->GetStringUTFChars(e, s, NULL) ; 
   iret = access(cp,R_OK);
   if (! iret)      ret = JNI_TRUE;
#if 0
   printf("*e=%x  o=%x  s=%x  s=%s iret=%d\n",e,o,cp,cp,iret);
#endif
   return ret;
}

java プログラムを実行します

> java tstJNI

import java.io.*;

public class tstJNI {
   static final String  fname="tstJNI.java";
   private native boolean canRead(String s);

   public static void main(String argv[]) {
      tstJNI    tt = new tstJNI();

      System.loadLibrary("tstJNI");
      if (tt.canRead(fname))  {
         try {
           FileInputStream f = new FileInputStream(fname);
           int b;

           while((b=f.read()) != -1) {
              System.out.print((char) b);
           }
           System.out.flush();
         } catch (IOException e) {  e.printStackTrace(); }
      }
      else System.out.println(fname +" can't open");
   }
}

JNIEnv 構造体

JNIEnv 構造体を示します。

typedef const struct JNINativeInterface_ *JNIEnv;
struct JNINativeInterface_ {
    void *reserved0;
    void *reserved1;
    void *reserved2;

    void *reserved3;
    jint (JNICALL *GetVersion)(JNIEnv *env);

    jclass (JNICALL *DefineClass)
      (JNIEnv *env, const char *name, jobject loader, const jbyte *buf,
       jsize len);
    jclass (JNICALL *FindClass)
      (JNIEnv *env, const char *name);

    jmethodID (JNICALL *FromReflectedMethod)
      (JNIEnv *env, jobject method);
    jfieldID (JNICALL *FromReflectedField)
      (JNIEnv *env, jobject field);

    jobject (JNICALL *ToReflectedMethod)
      (JNIEnv *env, jclass cls, jmethodID methodID, jboolean isStatic);

    jclass (JNICALL *GetSuperclass)
      (JNIEnv *env, jclass sub);
    jboolean (JNICALL *IsAssignableFrom)
      (JNIEnv *env, jclass sub, jclass sup);

    jobject (JNICALL *ToReflectedField)
      (JNIEnv *env, jclass cls, jfieldID fieldID, jboolean isStatic);

    jint (JNICALL *Throw)
      (JNIEnv *env, jthrowable obj);
    jint (JNICALL *ThrowNew)
      (JNIEnv *env, jclass clazz, const char *msg);
    jthrowable (JNICALL *ExceptionOccurred)
      (JNIEnv *env);
    void (JNICALL *ExceptionDescribe)
      (JNIEnv *env);
    void (JNICALL *ExceptionClear)
      (JNIEnv *env);
    void (JNICALL *FatalError)
      (JNIEnv *env, const char *msg);

    jint (JNICALL *PushLocalFrame)
      (JNIEnv *env, jint capacity);
    jobject (JNICALL *PopLocalFrame)
      (JNIEnv *env, jobject result);

    jobject (JNICALL *NewGlobalRef)
      (JNIEnv *env, jobject lobj);
    void (JNICALL *DeleteGlobalRef)
      (JNIEnv *env, jobject gref);
    void (JNICALL *DeleteLocalRef)
      (JNIEnv *env, jobject obj);
    jboolean (JNICALL *IsSameObject)
      (JNIEnv *env, jobject obj1, jobject obj2);
    jobject (JNICALL *NewLocalRef)
      (JNIEnv *env, jobject ref);
    jint (JNICALL *EnsureLocalCapacity)
      (JNIEnv *env, jint capacity);

    jobject (JNICALL *AllocObject)
      (JNIEnv *env, jclass clazz);
    jobject (JNICALL *NewObject)
      (JNIEnv *env, jclass clazz, jmethodID methodID, ...);
    jobject (JNICALL *NewObjectV)
      (JNIEnv *env, jclass clazz, jmethodID methodID, va_list args);
    jobject (JNICALL *NewObjectA)
      (JNIEnv *env, jclass clazz, jmethodID methodID, jvalue *args);

    jclass (JNICALL *GetObjectClass)
      (JNIEnv *env, jobject obj);
    jboolean (JNICALL *IsInstanceOf)
      (JNIEnv *env, jobject obj, jclass clazz);

    jmethodID (JNICALL *GetMethodID)
      (JNIEnv *env, jclass clazz, const char *name, const char *sig);

    jobject (JNICALL *CallObjectMethod)
      (JNIEnv *env, jobject obj, jmethodID methodID, ...);
    jobject (JNICALL *CallObjectMethodV)
      (JNIEnv *env, jobject obj, jmethodID methodID, va_list args);
    jobject (JNICALL *CallObjectMethodA)
      (JNIEnv *env, jobject obj, jmethodID methodID, jvalue * args);


    jboolean (JNICALL *CallBooleanMethod)
      (JNIEnv *env, jobject obj, jmethodID methodID, ...);
    jboolean (JNICALL *CallBooleanMethodV)
      (JNIEnv *env, jobject obj, jmethodID methodID, va_list args);
    jboolean (JNICALL *CallBooleanMethodA)
      (JNIEnv *env, jobject obj, jmethodID methodID, jvalue * args);

    jbyte (JNICALL *CallByteMethod)
      (JNIEnv *env, jobject obj, jmethodID methodID, ...);
    jbyte (JNICALL *CallByteMethodV)
      (JNIEnv *env, jobject obj, jmethodID methodID, va_list args);
    jbyte (JNICALL *CallByteMethodA)
      (JNIEnv *env, jobject obj, jmethodID methodID, jvalue *args);

    jchar (JNICALL *CallCharMethod)
      (JNIEnv *env, jobject obj, jmethodID methodID, ...);
    jchar (JNICALL *CallCharMethodV)
      (JNIEnv *env, jobject obj, jmethodID methodID, va_list args);
    jchar (JNICALL *CallCharMethodA)
      (JNIEnv *env, jobject obj, jmethodID methodID, jvalue *args);


    jshort (JNICALL *CallShortMethod)
      (JNIEnv *env, jobject obj, jmethodID methodID, ...);
    jshort (JNICALL *CallShortMethodV)
      (JNIEnv *env, jobject obj, jmethodID methodID, va_list args);
    jshort (JNICALL *CallShortMethodA)
      (JNIEnv *env, jobject obj, jmethodID methodID, jvalue *args);

    jint (JNICALL *CallIntMethod)
      (JNIEnv *env, jobject obj, jmethodID methodID, ...);
    jint (JNICALL *CallIntMethodV)
      (JNIEnv *env, jobject obj, jmethodID methodID, va_list args);
    jint (JNICALL *CallIntMethodA)
      (JNIEnv *env, jobject obj, jmethodID methodID, jvalue *args);

    jlong (JNICALL *CallLongMethod)
      (JNIEnv *env, jobject obj, jmethodID methodID, ...);
    jlong (JNICALL *CallLongMethodV)
      (JNIEnv *env, jobject obj, jmethodID methodID, va_list args);
    jlong (JNICALL *CallLongMethodA)
      (JNIEnv *env, jobject obj, jmethodID methodID, jvalue *args);


    jfloat (JNICALL *CallFloatMethod)
      (JNIEnv *env, jobject obj, jmethodID methodID, ...);
    jfloat (JNICALL *CallFloatMethodV)
      (JNIEnv *env, jobject obj, jmethodID methodID, va_list args);
    jfloat (JNICALL *CallFloatMethodA)
      (JNIEnv *env, jobject obj, jmethodID methodID, jvalue *args);

    jdouble (JNICALL *CallDoubleMethod)
      (JNIEnv *env, jobject obj, jmethodID methodID, ...);
    jdouble (JNICALL *CallDoubleMethodV)
      (JNIEnv *env, jobject obj, jmethodID methodID, va_list args);
    jdouble (JNICALL *CallDoubleMethodA)
      (JNIEnv *env, jobject obj, jmethodID methodID, jvalue *args);

    void (JNICALL *CallVoidMethod)
      (JNIEnv *env, jobject obj, jmethodID methodID, ...);
    void (JNICALL *CallVoidMethodV)
      (JNIEnv *env, jobject obj, jmethodID methodID, va_list args);
    void (JNICALL *CallVoidMethodA)
      (JNIEnv *env, jobject obj, jmethodID methodID, jvalue * args);

    jobject (JNICALL *CallNonvirtualObjectMethod)
      (JNIEnv *env, jobject obj, jclass clazz, jmethodID methodID, ...);
    jobject (JNICALL *CallNonvirtualObjectMethodV)
      (JNIEnv *env, jobject obj, jclass clazz, jmethodID methodID,
       va_list args);
    jobject (JNICALL *CallNonvirtualObjectMethodA)
      (JNIEnv *env, jobject obj, jclass clazz, jmethodID methodID,
       jvalue * args);

    jboolean (JNICALL *CallNonvirtualBooleanMethod)
      (JNIEnv *env, jobject obj, jclass clazz, jmethodID methodID, ...);
    jboolean (JNICALL *CallNonvirtualBooleanMethodV)
      (JNIEnv *env, jobject obj, jclass clazz, jmethodID methodID,
       va_list args);
    jboolean (JNICALL *CallNonvirtualBooleanMethodA)
      (JNIEnv *env, jobject obj, jclass clazz, jmethodID methodID,
       jvalue * args);

    jbyte (JNICALL *CallNonvirtualByteMethod)
      (JNIEnv *env, jobject obj, jclass clazz, jmethodID methodID, ...);
    jbyte (JNICALL *CallNonvirtualByteMethodV)
      (JNIEnv *env, jobject obj, jclass clazz, jmethodID methodID,
       va_list args);
    jbyte (JNICALL *CallNonvirtualByteMethodA)
      (JNIEnv *env, jobject obj, jclass clazz, jmethodID methodID,
       jvalue *args);

    jchar (JNICALL *CallNonvirtualCharMethod)
      (JNIEnv *env, jobject obj, jclass clazz, jmethodID methodID, ...);
    jchar (JNICALL *CallNonvirtualCharMethodV)
      (JNIEnv *env, jobject obj, jclass clazz, jmethodID methodID,
       va_list args);
    jchar (JNICALL *CallNonvirtualCharMethodA)
      (JNIEnv *env, jobject obj, jclass clazz, jmethodID methodID,
       jvalue *args);

    jshort (JNICALL *CallNonvirtualShortMethod)
      (JNIEnv *env, jobject obj, jclass clazz, jmethodID methodID, ...);
    jshort (JNICALL *CallNonvirtualShortMethodV)
      (JNIEnv *env, jobject obj, jclass clazz, jmethodID methodID,
       va_list args);
    jshort (JNICALL *CallNonvirtualShortMethodA)
      (JNIEnv *env, jobject obj, jclass clazz, jmethodID methodID,
       jvalue *args);

    jint (JNICALL *CallNonvirtualIntMethod)
      (JNIEnv *env, jobject obj, jclass clazz, jmethodID methodID, ...);
    jint (JNICALL *CallNonvirtualIntMethodV)
      (JNIEnv *env, jobject obj, jclass clazz, jmethodID methodID,
       va_list args);
    jint (JNICALL *CallNonvirtualIntMethodA)
      (JNIEnv *env, jobject obj, jclass clazz, jmethodID methodID,
       jvalue *args);

    jlong (JNICALL *CallNonvirtualLongMethod)
      (JNIEnv *env, jobject obj, jclass clazz, jmethodID methodID, ...);
    jlong (JNICALL *CallNonvirtualLongMethodV)
      (JNIEnv *env, jobject obj, jclass clazz, jmethodID methodID,
       va_list args);
    jlong (JNICALL *CallNonvirtualLongMethodA)
      (JNIEnv *env, jobject obj, jclass clazz, jmethodID methodID,
       jvalue *args);

    jfloat (JNICALL *CallNonvirtualFloatMethod)
      (JNIEnv *env, jobject obj, jclass clazz, jmethodID methodID, ...);
    jfloat (JNICALL *CallNonvirtualFloatMethodV)
      (JNIEnv *env, jobject obj, jclass clazz, jmethodID methodID,
       va_list args);
    jfloat (JNICALL *CallNonvirtualFloatMethodA)
      (JNIEnv *env, jobject obj, jclass clazz, jmethodID methodID,
       jvalue *args);

    jdouble (JNICALL *CallNonvirtualDoubleMethod)
      (JNIEnv *env, jobject obj, jclass clazz, jmethodID methodID, ...);
    jdouble (JNICALL *CallNonvirtualDoubleMethodV)
      (JNIEnv *env, jobject obj, jclass clazz, jmethodID methodID,
       va_list args);
    jdouble (JNICALL *CallNonvirtualDoubleMethodA)
      (JNIEnv *env, jobject obj, jclass clazz, jmethodID methodID,
       jvalue *args);

    void (JNICALL *CallNonvirtualVoidMethod)
      (JNIEnv *env, jobject obj, jclass clazz, jmethodID methodID, ...);
    void (JNICALL *CallNonvirtualVoidMethodV)
      (JNIEnv *env, jobject obj, jclass clazz, jmethodID methodID,
       va_list args);
    void (JNICALL *CallNonvirtualVoidMethodA)
      (JNIEnv *env, jobject obj, jclass clazz, jmethodID methodID,
       jvalue * args);

    jfieldID (JNICALL *GetFieldID)
      (JNIEnv *env, jclass clazz, const char *name, const char *sig);

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

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

    jmethodID (JNICALL *GetStaticMethodID)
      (JNIEnv *env, jclass clazz, const char *name, const char *sig);

    jobject (JNICALL *CallStaticObjectMethod)
      (JNIEnv *env, jclass clazz, jmethodID methodID, ...);
    jobject (JNICALL *CallStaticObjectMethodV)
      (JNIEnv *env, jclass clazz, jmethodID methodID, va_list args);
    jobject (JNICALL *CallStaticObjectMethodA)
      (JNIEnv *env, jclass clazz, jmethodID methodID, jvalue *args);

    jboolean (JNICALL *CallStaticBooleanMethod)
      (JNIEnv *env, jclass clazz, jmethodID methodID, ...);
    jboolean (JNICALL *CallStaticBooleanMethodV)
      (JNIEnv *env, jclass clazz, jmethodID methodID, va_list args);
    jboolean (JNICALL *CallStaticBooleanMethodA)
      (JNIEnv *env, jclass clazz, jmethodID methodID, jvalue *args);

    jbyte (JNICALL *CallStaticByteMethod)
      (JNIEnv *env, jclass clazz, jmethodID methodID, ...);
    jbyte (JNICALL *CallStaticByteMethodV)
      (JNIEnv *env, jclass clazz, jmethodID methodID, va_list args);
    jbyte (JNICALL *CallStaticByteMethodA)
      (JNIEnv *env, jclass clazz, jmethodID methodID, jvalue *args);

    jchar (JNICALL *CallStaticCharMethod)
      (JNIEnv *env, jclass clazz, jmethodID methodID, ...);
    jchar (JNICALL *CallStaticCharMethodV)
      (JNIEnv *env, jclass clazz, jmethodID methodID, va_list args);
    jchar (JNICALL *CallStaticCharMethodA)
      (JNIEnv *env, jclass clazz, jmethodID methodID, jvalue *args);

    jshort (JNICALL *CallStaticShortMethod)
      (JNIEnv *env, jclass clazz, jmethodID methodID, ...);
    jshort (JNICALL *CallStaticShortMethodV)
      (JNIEnv *env, jclass clazz, jmethodID methodID, va_list args);
    jshort (JNICALL *CallStaticShortMethodA)
      (JNIEnv *env, jclass clazz, jmethodID methodID, jvalue *args);

    jint (JNICALL *CallStaticIntMethod)
      (JNIEnv *env, jclass clazz, jmethodID methodID, ...);
    jint (JNICALL *CallStaticIntMethodV)
      (JNIEnv *env, jclass clazz, jmethodID methodID, va_list args);
    jint (JNICALL *CallStaticIntMethodA)
      (JNIEnv *env, jclass clazz, jmethodID methodID, jvalue *args);

    jlong (JNICALL *CallStaticLongMethod)
      (JNIEnv *env, jclass clazz, jmethodID methodID, ...);
    jlong (JNICALL *CallStaticLongMethodV)
      (JNIEnv *env, jclass clazz, jmethodID methodID, va_list args);
    jlong (JNICALL *CallStaticLongMethodA)
      (JNIEnv *env, jclass clazz, jmethodID methodID, jvalue *args);

    jfloat (JNICALL *CallStaticFloatMethod)
      (JNIEnv *env, jclass clazz, jmethodID methodID, ...);
    jfloat (JNICALL *CallStaticFloatMethodV)
      (JNIEnv *env, jclass clazz, jmethodID methodID, va_list args);
    jfloat (JNICALL *CallStaticFloatMethodA)
      (JNIEnv *env, jclass clazz, jmethodID methodID, jvalue *args);

    jdouble (JNICALL *CallStaticDoubleMethod)
      (JNIEnv *env, jclass clazz, jmethodID methodID, ...);
    jdouble (JNICALL *CallStaticDoubleMethodV)
      (JNIEnv *env, jclass clazz, jmethodID methodID, va_list args);
    jdouble (JNICALL *CallStaticDoubleMethodA)
      (JNIEnv *env, jclass clazz, jmethodID methodID, jvalue *args);

    void (JNICALL *CallStaticVoidMethod)
      (JNIEnv *env, jclass cls, jmethodID methodID, ...);
    void (JNICALL *CallStaticVoidMethodV)
      (JNIEnv *env, jclass cls, jmethodID methodID, va_list args);
    void (JNICALL *CallStaticVoidMethodA)
      (JNIEnv *env, jclass cls, jmethodID methodID, jvalue * args);

    jfieldID (JNICALL *GetStaticFieldID)
      (JNIEnv *env, jclass clazz, const char *name, const char *sig);
    jobject (JNICALL *GetStaticObjectField)
      (JNIEnv *env, jclass clazz, jfieldID fieldID);
    jboolean (JNICALL *GetStaticBooleanField)
      (JNIEnv *env, jclass clazz, jfieldID fieldID);
    jbyte (JNICALL *GetStaticByteField)
      (JNIEnv *env, jclass clazz, jfieldID fieldID);
    jchar (JNICALL *GetStaticCharField)
      (JNIEnv *env, jclass clazz, jfieldID fieldID);
    jshort (JNICALL *GetStaticShortField)
      (JNIEnv *env, jclass clazz, jfieldID fieldID);
    jint (JNICALL *GetStaticIntField)
      (JNIEnv *env, jclass clazz, jfieldID fieldID);
    jlong (JNICALL *GetStaticLongField)
      (JNIEnv *env, jclass clazz, jfieldID fieldID);
    jfloat (JNICALL *GetStaticFloatField)
      (JNIEnv *env, jclass clazz, jfieldID fieldID);
    jdouble (JNICALL *GetStaticDoubleField)
      (JNIEnv *env, jclass clazz, jfieldID fieldID);

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

    jstring (JNICALL *NewString)
      (JNIEnv *env, const jchar *unicode, jsize len);
    jsize (JNICALL *GetStringLength)
      (JNIEnv *env, jstring str);
    const jchar *(JNICALL *GetStringChars)
      (JNIEnv *env, jstring str, jboolean *isCopy);
    void (JNICALL *ReleaseStringChars)
      (JNIEnv *env, jstring str, const jchar *chars);

    jstring (JNICALL *NewStringUTF)
      (JNIEnv *env, const char *utf);
    jsize (JNICALL *GetStringUTFLength)
      (JNIEnv *env, jstring str);
    const char* (JNICALL *GetStringUTFChars)
      (JNIEnv *env, jstring str, jboolean *isCopy);
    void (JNICALL *ReleaseStringUTFChars)
      (JNIEnv *env, jstring str, const char* chars);

    jsize (JNICALL *GetArrayLength)
      (JNIEnv *env, jarray array);

    jobjectArray (JNICALL *NewObjectArray)
      (JNIEnv *env, jsize len, jclass clazz, jobject init);
    jobject (JNICALL *GetObjectArrayElement)
      (JNIEnv *env, jobjectArray array, jsize index);
    void (JNICALL *SetObjectArrayElement)
      (JNIEnv *env, jobjectArray array, jsize index, jobject val);

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

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

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

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

    void (JNICALL *SetBooleanArrayRegion)
      (JNIEnv *env, jbooleanArray array, jsize start, jsize l, jboolean *buf);
    void (JNICALL *SetByteArrayRegion)
      (JNIEnv *env, jbyteArray array, jsize start, jsize len, jbyte *buf);
    void (JNICALL *SetCharArrayRegion)
      (JNIEnv *env, jcharArray array, jsize start, jsize len, jchar *buf);
    void (JNICALL *SetShortArrayRegion)
      (JNIEnv *env, jshortArray array, jsize start, jsize len, jshort *buf);
    void (JNICALL *SetIntArrayRegion)
      (JNIEnv *env, jintArray array, jsize start, jsize len, jint *buf);
    void (JNICALL *SetLongArrayRegion)
      (JNIEnv *env, jlongArray array, jsize start, jsize len, jlong *buf);
    void (JNICALL *SetFloatArrayRegion)
      (JNIEnv *env, jfloatArray array, jsize start, jsize len, jfloat *buf);
    void (JNICALL *SetDoubleArrayRegion)
      (JNIEnv *env, jdoubleArray array, jsize start, jsize len, jdouble *buf);

    jint (JNICALL *RegisterNatives)
      (JNIEnv *env, jclass clazz, const JNINativeMethod *methods,
       jint nMethods);
    jint (JNICALL *UnregisterNatives)
      (JNIEnv *env, jclass clazz);

    jint (JNICALL *MonitorEnter)
      (JNIEnv *env, jobject obj);
    jint (JNICALL *MonitorExit)
      (JNIEnv *env, jobject obj);

    jint (JNICALL *GetJavaVM)
      (JNIEnv *env, JavaVM **vm);

    void (JNICALL *GetStringRegion)
      (JNIEnv *env, jstring str, jsize start, jsize len, jchar *buf);
    void (JNICALL *GetStringUTFRegion)
      (JNIEnv *env, jstring str, jsize start, jsize len, char *buf);

    void * (JNICALL *GetPrimitiveArrayCritical)
      (JNIEnv *env, jarray array, jboolean *isCopy);
    void (JNICALL *ReleasePrimitiveArrayCritical)
      (JNIEnv *env, jarray array, void *carray, jint mode);

    const jchar * (JNICALL *GetStringCritical)
      (JNIEnv *env, jstring string, jboolean *isCopy);
    void (JNICALL *ReleaseStringCritical)
      (JNIEnv *env, jstring string, const jchar *cstring);

    jweak (JNICALL *NewWeakGlobalRef)
       (JNIEnv *env, jobject obj);
    void (JNICALL *DeleteWeakGlobalRef)
       (JNIEnv *env, jweak ref);

    jboolean (JNICALL *ExceptionCheck)
       (JNIEnv *env);
};

[ 参考ページ ] 　　java sun JNI