Bug 726821 - Caching JNI class references should use a global reference. r=blassey

{

    if (initialized) return;

    objectClass       = jenv->FindClass("java/lang/Object");

    stringClass       = jenv->FindClass("java/lang/String");

    byteBufferClass   = jenv->FindClass("java/nio/ByteBuffer");

    cursorClass       = jenv->FindClass("org/mozilla/gecko/sqlite/MatrixBlobCursor");

    jclass lObjectClass       = jenv->FindClass("java/lang/Object");

    jclass lStringClass       = jenv->FindClass("java/lang/String");

    jclass lByteBufferClass   = jenv->FindClass("java/nio/ByteBuffer");

    jclass lCursorClass       = jenv->FindClass("org/mozilla/gecko/sqlite/MatrixBlobCursor");

    if (lStringClass == NULL

        || lObjectClass == NULL

        || lByteBufferClass == NULL

        || lCursorClass == NULL) {

        LOG("Error finding classes");

        JNI_Throw(jenv, "org/mozilla/gecko/sqlite/SQLiteBridgeException",

                  "FindClass error");

        return;

    }

    // Those are only local references. Make them global so they work

    // across calls and threads.

    objectClass = (jclass)jenv->NewGlobalRef(lObjectClass);

    stringClass = (jclass)jenv->NewGlobalRef(lStringClass);

    byteBufferClass = (jclass)jenv->NewGlobalRef(lByteBufferClass);

    cursorClass = (jclass)jenv->NewGlobalRef(lCursorClass);

    if (stringClass == NULL || objectClass == NULL

        || byteBufferClass == NULL

        || cursorClass == NULL) {

        LOG("Error finding classes");

        LOG("Error getting global references");

        JNI_Throw(jenv, "org/mozilla/gecko/sqlite/SQLiteBridgeException",

                  "FindClass error");

                  "NewGlobalRef error");

        return;

    }