问题描述
我真的很新的Java编程，因此我提前道歉，如果这听起来像一个愚蠢的问题。
I'm really new to java programming therefore I apologise in advance if this sounds like a stupid question.
我试图建立写在纯C一个简单的应用程序，它必须创建一个的JavaVM ，然后创建基于装载Java code一个新窗口 AWT / Swing的。
I'm trying to build a simple application written in plain C, which must create a JavaVM and then create a new window by loading java code based on AWT/Swing.
的技术说明我心中已经了解到，在Mac OSX上只，的JavaVM必须从主线程不同线程，以便能够根据AWT创建的GUI被调用。
Following this technical note I'v learned that in Mac OSX only, JavaVM must be invoked from a thread different from the main thread in order to be able to create a GUI based on AWT.
因此，在我的C应用程序的主的功能，我创建了一个执行的一切，从创建JAVAVM来创建图形用户界面的一个新的线程。
Therefore, in the main function of my C application I created a new thread that performs everything, from the creation of the javaVM to the creation of the GUI.
由于应用程序是不是在现实中那么简单，我将发布一个简化版本。
Since the application isn't in reality so simple, I will post a simplified version.
主要功能：
int main(int argc, char** argv)
{
// Run-time loading of JavaVM framework
void *result;
result = dlopen("/System/Library/Frameworks/JavaVM.framework/JavaVM", RTLD_LAZY);
if (!result) {
printf("can't open library JavaVM: %s\n", dlerror());
}
else {
printf("library JavaVM loaded\n");
}
/* Start the thread that runs the VM. */
pthread_t vmthread;
// create a new pthread copying the stack size of the primordial pthread
struct rlimit limit;
size_t stack_size = 0;
int rc = getrlimit(RLIMIT_STACK, &limit);
if (rc == 0) {
if (limit.rlim_cur != 0LL) {
stack_size = (size_t)limit.rlim_cur;
}
}
pthread_attr_t thread_attr;
pthread_attr_init(&thread_attr);
pthread_attr_setscope(&thread_attr, PTHREAD_SCOPE_SYSTEM);
pthread_attr_setdetachstate(&thread_attr, PTHREAD_CREATE_DETACHED);
if (stack_size > 0) {
pthread_attr_setstacksize(&thread_attr, stack_size);
}
/* Start the thread that we will start the JVM on. */
pthread_create(&vmthread, &thread_attr, startJava, (void *)&thread_data_struct);
pthread_attr_destroy(&thread_attr);
pthread_exit(NULL);
return 0;
}
线程函数：
void *startJava(void *jvm_lib)
{
JavaVMInitArgs args;
const char* classpath = getenv("CLASSPATH");
// determine classpath
char* classpath_opt = str_printf("-Djava.class.path=%s", classpath);
JavaVMOption* option = malloc(sizeof(JavaVMOption) * 2);
option[0].optionString = classpath_opt;
option[1].optionString = str_printf("-verbose:jni");
args.version = JNI_VERSION_1_6;
args.nOptions = 2;
args.options = option;
args.ignoreUnrecognized = JNI_FALSE; // don't ignore unrecognized options
fptr_JNI_CreateJavaVM JNI_CreateJavaVM_fp = (fptr_JNI_CreateJavaVM)dl_dlsym(jvm_lib,
"JNI_CreateJavaVM");
int result = JNI_CreateJavaVM_fp(&jvm, (void**) &env, &args);
free(option);
free(classpath_opt);
// launch java code
jclass init_class = (*env)->FindClass(env, "org/classes/Loader");
jmethodID load_id = (*env)->GetStaticMethodID(env, init_class, "Load",
"(Ljava/lang/String;Lorg/classes/stuff;J)V");
(*env)->CallStaticVoidMethod(env, init_class, load_id);
}
的Java code：（修订版）
package org.classes;
import java.awt.AWTException;
import java.awt.Component;
import java.awt.Frame;
import java.awt.image.BufferedImage;
import java.awt.EventQueue;
public class Loader {
public static void Load(String baseDir, Stuff stuff, long nativePointer)
{
EventQueue.invokeLater(new Runnable() {
public void run() {
System.loadLibrary("drawingHelperLibrary");
...
...
...
// start test window
Frame frame = new Frame();
frame.setSize(640,480);
frame.setLocation(50, 50);
frame.setVisible(true);
}
});
}
}
以上所有code的成功执行，除了创建导致死锁或由于终端类似的东西窗口依然繁忙，没有任何CPU使用率，以及这两个线程仍然活着。
All of the above code executes successfully except for the creation of the window which causes a deadlock or something similar since terminal remains busy without any CPU usage and both threads remain alive.
如果我注释掉有关窗口创建线，应用成功执行并退出。
If I comment out the lines concerning the creation of the window, the application execute successfully and quit.
这是从jstack输出：
This is the output from jstack:
Full thread dump Java HotSpot(TM) 64-Bit Server VM (20.4-b02-402 mixed mode):
"Attach Listener" daemon prio=9 tid=1040b1800 nid=0x11b888000 waiting on condition [00000000]
java.lang.Thread.State: RUNNABLE
"Low Memory Detector" daemon prio=5 tid=103806000 nid=0x10b137000 runnable [00000000]
java.lang.Thread.State: RUNNABLE
"C2 CompilerThread1" daemon prio=9 tid=103805800 nid=0x10b034000 waiting on condition [00000000]
java.lang.Thread.State: RUNNABLE
"C2 CompilerThread0" daemon prio=9 tid=103804800 nid=0x10af31000 waiting on condition [00000000]
java.lang.Thread.State: RUNNABLE
"Signal Dispatcher" daemon prio=9 tid=103804000 nid=0x10ae2e000 runnable [00000000]
java.lang.Thread.State: RUNNABLE
"Surrogate Locker Thread (Concurrent GC)" daemon prio=5 tid=103803000 nid=0x10ad2b000 waiting on condition [00000000]
java.lang.Thread.State: RUNNABLE
"Finalizer" daemon prio=8 tid=10409b800 nid=0x10ac28000 in Object.wait() [10ac27000]
java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
- waiting on <7f3001300> (a java.lang.ref.ReferenceQueue$Lock)
at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:118)
- locked <7f3001300> (a java.lang.ref.ReferenceQueue$Lock)
at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:134)
at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:159)
"Reference Handler" daemon prio=10 tid=10409b000 nid=0x10ab25000 in Object.wait() [10ab24000]
java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
- waiting on <7f30011d8> (a java.lang.ref.Reference$Lock)
at java.lang.Object.wait(Object.java:485)
at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:116)
- locked <7f30011d8> (a java.lang.ref.Reference$Lock)
"main" prio=5 tid=104000800 nid=0x10048d000 runnable [10048a000]
java.lang.Thread.State: RUNNABLE
at java.lang.ClassLoader$NativeLibrary.load(Native Method)
at java.lang.ClassLoader.loadLibrary0(ClassLoader.java:1827)
- locked <7f30010a8> (a java.util.Vector)
- locked <7f3001100> (a java.util.Vector)
at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1724)
at java.lang.Runtime.loadLibrary0(Runtime.java:823)
- locked <7f3004e90> (a java.lang.Runtime)
at java.lang.System.loadLibrary(System.java:1045)
at sun.security.action.LoadLibraryAction.run(LoadLibraryAction.java:50)
at java.security.AccessController.doPrivileged(Native Method)
at sun.awt.NativeLibLoader.loadLibraries(NativeLibLoader.java:38)
at sun.awt.DebugHelper.<clinit>(DebugHelper.java:29)
at java.awt.Component.<clinit>(Component.java:566)
at org.classes.Loader.Load(Loader.java:69)
"VM Thread" prio=9 tid=104096000 nid=0x10aa22000 runnable
"Gang worker#0 (Parallel GC Threads)" prio=9 tid=104002000 nid=0x103504000 runnable
"Gang worker#1 (Parallel GC Threads)" prio=9 tid=104002800 nid=0x103607000 runnable
"Concurrent Mark-Sweep GC Thread" prio=9 tid=10404d000 nid=0x10a6f0000 runnable
"VM Periodic Task Thread" prio=10 tid=103817800 nid=0x10b23a000 waiting on condition
"Exception Catcher Thread" prio=10 tid=104001800 nid=0x103401000 runnable
JNI global references: 913
我真的不知道还有什么我可以做。也许这是一个愚蠢的错误，但我没有足够的熟练使用这个Java-C组合，因为它是我在寻找它的第一次。
I really don't know what more can I do. Maybe it's a stupid mistake but I'm not skilled enough with this Java-C mix since it's the first time that I'm looking at it.
更新：我已经更新了Java code（感谢trashgod），但它仍然无法正常工作。
我缺少的东西吗？
UPDATE: I have updated the java code (thanks to trashgod) but it still doesn't work.Am I missing something?
推荐答案
我可以通过查看Eclipse项目是如何创建它的发射器来解决这个问题。您需要产卵的JVM的一个单独的线程，你都做了，但最主要的方法需要启动CFRunLoop。
I was able to resolve this issue by looking at how the Eclipse project creates its launchers. You need to spawn a separate thread for the JVM as you have done, but the main method needs to start the CFRunLoop.
有可能是您的特定实现一些额外的细节，但与此类似，目前在我们的案子：
There might be some additional details for your particular implementation, but something similar to this is currently working in our case:
...
#include <CoreServices/CoreServices.h>
static void dummyCallback(void * info) {}
...
...
if (stack_size > 0) {
pthread_attr_setstacksize(&thread_attr, stack_size);
}
CFRunLoopRef loopRef = CFRunLoopGetCurrent();
/* Start the thread that we will start the JVM on. */
pthread_create(&vmthread, &thread_attr, startJava, (void *)&thread_data_struct);
pthread_attr_destroy(&thread_attr);
CFRunLoopSourceContext sourceContext = {
.version = 0, .info = NULL, .retain = NULL, .release = NULL,
.copyDescription = NULL, .equal = NULL, .hash = NULL,
.schedule = NULL, .cancel = NULL, .perform = &dummyCallback };
CFRunLoopSourceRef sourceRef = CFRunLoopSourceCreate(NULL, 0, &sourceContext);
CFRunLoopAddSource(loopRef, sourceRef, kCFRunLoopCommonModes);
CFRunLoopRun();
CFRelease(sourceRef);
...
您可以查看通过Eclipse执行此：
You can look through the Eclipse implementation here:
http://git.eclipse.org/c/equinox/rt.equinox.framework.git
这篇关于OSX：JavaVM的，AWT / Swing和可能死锁的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！