JNI_ENTRY(jfieldID, jni_GetFieldID(JNIEnv *env, jclass clazz,
          const char *name, const char *sig))

  {- -------------------------------------------
  (1) (デバッグ用の処理)
      (See: JNIWrapper)
      ---------------------------------------- -}

      JNIWrapper("GetFieldID");

  {- -------------------------------------------
  (1) (DTrace のフック点)
      ---------------------------------------- -}

      DTRACE_PROBE4(hotspot_jni, GetFieldID__entry, env, clazz, name, sig);

  {- -------------------------------------------
  (1) (変数宣言など)
      ---------------------------------------- -}

      jfieldID ret = 0;

  {- -------------------------------------------
  (1) (DTrace のフック点)(リターン用) (See: DT_RETURN_MARK)
      ---------------------------------------- -}

      DT_RETURN_MARK(GetFieldID, jfieldID, (const jfieldID&)ret);

  {- -------------------------------------------
  (1) (変数宣言など)
      ---------------------------------------- -}

      // The class should have been loaded (we have an instance of the class
      // passed in) so the field and signature should already be in the symbol
      // table.  If they're not there, the field doesn't exist.
      TempNewSymbol fieldname = SymbolTable::probe(name, (int)strlen(name));
      TempNewSymbol signame = SymbolTable::probe(sig, (int)strlen(sig));

  {- -------------------------------------------
  (1) もし指定されたフィールド名やシグネチャが SynbolTable 内に見つからなければ, NoSuchMethodError.
      ---------------------------------------- -}

      if (fieldname == NULL || signame == NULL) {
        THROW_MSG_0(vmSymbols::java_lang_NoSuchFieldError(), (char*) name);
      }

  {- -------------------------------------------
  (1) (変数宣言など)
      ---------------------------------------- -}

      KlassHandle k(THREAD,
                    java_lang_Class::as_klassOop(JNIHandles::resolve_non_null(clazz)));

  {- -------------------------------------------
  (1) 対象のクラスオブジェクトに対して Klass::initialize() を呼び, 
      リンクや初期化が終わっていなければ終わらせておく.
      ---------------------------------------- -}

      // Make sure class is initialized before handing id's out to fields
      Klass::cast(k())->initialize(CHECK_NULL);

  {- -------------------------------------------
  (1) instanceKlass::find_field() を呼んで, 指定されたフィールドの情報を取得する.

      (instanceKlass::find_field() で見つからなかった場合や
       そもそも instanceKlass ではなかった場合は, NoSuchFieldError.)
      ---------------------------------------- -}

      fieldDescriptor fd;
      if (!Klass::cast(k())->oop_is_instance() ||
          !instanceKlass::cast(k())->find_field(fieldname, signame, false, &fd)) {
        THROW_MSG_0(vmSymbols::java_lang_NoSuchFieldError(), (char*) name);
      }

  {- -------------------------------------------
  (1) jfieldIDWorkaround::to_instance_jfieldID() を呼んで, 
      取得したフィールド情報を jfieldID 化し, 
      結果をリターン.
      ---------------------------------------- -}

      // A jfieldID for a non-static field is simply the offset of the field within the instanceOop
      // It may also have hash bits for k, if VerifyJNIFields is turned on.
      ret = jfieldIDWorkaround::to_instance_jfieldID(k(), fd.offset());
      return ret;
    JNI_END