/* * Copyright (c) 2020 Alibaba Group Holding Limited. All Rights Reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Alibaba designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. */ #include #include #include #include #include JavaVM *jvm; /* denotes a Java VM */ jobject lock; volatile int fooGotLock; int main() { JNIEnv *env; JavaVMInitArgs vm_args; /* JDK/JRE 6 VM initialization arguments */ JavaVMOption options[5]; options[0].optionString = "-XX:+UnlockExperimentalVMOptions"; options[1].optionString = "-XX:+EnableCoroutine"; options[2].optionString = "-XX:-UseBiasedLocking"; options[3].optionString = "-Dcom.alibaba.transparentAsync=true"; options[4].optionString = "-XX:+UseWispMonitor"; vm_args.version = JNI_VERSION_1_6; vm_args.nOptions = 5; vm_args.options = options; vm_args.ignoreUnrecognized = false; /* load and initialize a Java VM, return a JNI interface * pointer in env */ if (JNI_CreateJavaVM(&jvm, (void**)&env, &vm_args) != JNI_OK) { exit(-1); } jclass cls = env->FindClass("java/nio/channels/spi/SelectorProvider"); printf("class = %p\n", cls); jfieldID fid = env->GetStaticFieldID(cls, "lock", "Ljava/lang/Object;"); printf("fid = %p\n", fid); lock = env->GetStaticObjectField(cls, fid); printf("lock = %p\n", lock); pthread_t tid; void *foo(void *arg); pthread_create(&tid, NULL, foo, NULL); while (!fooGotLock) ; // wait if (env->MonitorEnter(lock) != JNI_OK) { exit(-1); } return jvm->DestroyJavaVM() == JNI_OK ? 0 : -1; } void *foo(void *arg) { JNIEnv *env; if (jvm->AttachCurrentThread((void**)&env, NULL) != JNI_OK) { exit(-1); } if (env->MonitorEnter(lock) != JNI_OK) { exit(-1); } fooGotLock = 1; usleep(100 * 1000); // 100 ms if (jvm->DetachCurrentThread() != JNI_OK) { // unpark main thread exit(-1); } return NULL; }