Name: boT120536 Date: 03/07/2001


java version "1.3.0"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.0-C)
Java HotSpot(TM) Client VM (build 1.3.0-C, mixed mode)

When a native method creates a thread, if the native method is called by a java
Runnable object which was started by javax.swing.SwingUtilities.invokeLater or
javax.swing.SwingUtilities.invokeAndWait, the native thread takes several
seconds to start.

  To reproduce the problem:
1. compile jnitest.java with javac
2. build the C header file with javah
3. build jnitest.c into a native library (cl -LD -MT jnitest.c)
4. run the example with this command line:
      java jnitest RunType

...where RunType is how the Runnable object should be executed
R = use Runnable.run
T = use the Thread object
L = use javax.swing.SwingUtilities.invokeLater
W = use javax.swing.SwingUtilities.invokeAndWait

e.g. java jnitest W

If the parameter is L or W, the thread will take several seconds to start.

// this is jnitest.java
class jnitest
{
   static native void count(int num);

   static
   {
      System.loadLibrary("jnitest");
   }

   public static void main(String[] args) throws Exception
   {
      Runnable run =
         new Runnable()
         {
            public void run()
            {
               long t1,t2;
               t1 = System.currentTimeMillis();
               count(0);
               t2 = System.currentTimeMillis();

               System.out.println("time = " + (t2 - t1));
               System.exit(0);
            }
         };

      switch(args[0].charAt(0))
      {
         case 'R':
            run.run();
            break;
         case 'L':
            javax.swing.SwingUtilities.invokeLater(run);
            break;
         case 'W':
            javax.swing.SwingUtilities.invokeAndWait(run);
            break;
         case 'T':
            (new Thread(run)).start();
            break;
      }
   }
}
// end of jnitest.java


/* this is jnitest.c */
#include "jnitest.h"
#include <windows.h>
#include <time.h>

void myThread(void *p)
{
   *((char *)p) = 'A';
}

JNIEXPORT void JNICALL Java_jnitest_count(JNIEnv *env, jclass t, jint count)
{
   int rc;
   clock_t clockStart;
   char buffer = ' ';

   rc = (int)_beginthread( myThread, 5000, &buffer ) ;
   clockStart = clock() ;
   while ( buffer == ' ' )
   {
      Sleep( 0 ) ;
   }
   puts("DONE");
}
/* end of jnitest.c */
(Review ID: 117945)
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