Why?When send a String type param from Java to C,I get An unexpected error.

Question

The error trace like this:
# An unexpected error has been detected by HotSpot Virtual Machine:
# EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x10001d9c, pid=1944, tid=3204
# Java VM: Java HotSpot(TM) Client VM (1.5.0_07-b03 mixed mode, sharing)
# Problematic frame:
# C [sample.dll+0x1d9c]
--------------- T H R E A D ---------------
Current thread (0x00036158): JavaThread "main" [_thread_in_native, id=3204]
siginfo: ExceptionCode=0xc0000005, reading address 0x00000051
Registers:
EAX=0x7ffffffe, EBX=0x26c24ad0, ECX=0x00000051, EDX=0x7fffffff
ESP=0x0007f748, EBP=0x0007f9fc, ESI=0x0007fa38, EDI=0x0007fa88
EIP=0x10001d9c, EFLAGS=0x00010206
Top of Stack: (sp=0x0007f748)
0x0007f748: 0007fa88 0007fa38 26c24ad0 7c930738
0x0007f758: 7fffffff 00000030 7c931596 7c9306eb
0x0007f768: 00000007 00000008 26c24ad0 0007f788
0x0007f778: 0007f7b4 00ae29a4 00000000 22bf60d0
0x0007f788: 10001005 00000000 00000001 00000000
0x0007f798: 0007f790 02eb02b0 0007f7e0 7ffffffe
0x0007f7a8: 00000000 00000051 0007f7dc 0007f7f4
0x0007f7b8: 00000000 00000000 00000000 00000000
Instructions: (pc=0x10001d9c)
0x10001d8c: 89 85 a8 fd ff ff 85 d2 74 1e 8b 8d b0 fd ff ff
0x10001d9c: 0f be 11 85 d2 74 11 8b 85 b0 fd ff ff 83 c0 01
Stack: [0x00040000,0x00080000), sp=0x0007f748, free space=253k
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
C [sample.dll+0x1d9c]
C [sample.dll+0x10ca]
C [sample.dll+0x12e7a]
j HelloWorld.sayHello(Ljava/lang/String;)V+0
j HelloWorld.main([Ljava/lang/String;)V+11
v ~StubRoutines::call_stub
V [jvm.dll+0x86401]
V [jvm.dll+0xdb172]
V [jvm.dll+0x862d2]
V [jvm.dll+0x8d2a2]
C [java.exe+0x14c5]
C [java.exe+0x69cd]
C [kernel32.dll+0x16d4f]
Java frames: (J=compiled Java code, j=interpreted, Vv=VM code)
j HelloWorld.sayHello(Ljava/lang/String;)V+0
j HelloWorld.main([Ljava/lang/String;)V+11
v ~StubRoutines::call_stub
--------------- P R O C E S S ---------------
Java Threads: ( => current thread )
0x00a7f6c8 JavaThread "Low Memory Detector" daemon [_thread_blocked, id=3216]
0x00a7e3c0 JavaThread "CompilerThread0" daemon [_thread_blocked, id=2040]
0x00a7d480 JavaThread "Signal Dispatcher" daemon [_thread_blocked, id=1760]
0x00a51f58 JavaThread "Finalizer" daemon [_thread_blocked, id=3212]
0x00a50a70 JavaThread "Reference Handler" daemon [_thread_blocked, id=3208]
=>0x00036158 JavaThread "main" [_thread_in_native, id=3204]
Other Threads:
0x00a4e178 VMThread [id=1952]
0x00a808e0 WatcherThread [id=3220]
VM state:not at safepoint (normal execution)
VM Mutex/Monitor currently owned by a thread: None
Heap
def new generation total 576K, used 238K [0x22bd0000, 0x22c70000, 0x230b0000)
eden space 512K, 46% used [0x22bd0000, 0x22c0b930, 0x22c50000)
from space 64K, 0% used [0x22c50000, 0x22c50000, 0x22c60000)
to space 64K, 0% used [0x22c60000, 0x22c60000, 0x22c70000)
tenured generation total 1408K, used 0K [0x230b0000, 0x23210000, 0x26bd0000)
the space 1408K, 0% used [0x230b0000, 0x230b0000, 0x230b0200, 0x23210000)
compacting perm gen total 8192K, used 339K [0x26bd0000, 0x273d0000, 0x2abd0000)
the space 8192K, 4% used [0x26bd0000, 0x26c24e90, 0x26c25000, 0x273d0000)
ro space 8192K, 67% used [0x2abd0000, 0x2b12d9f8, 0x2b12da00, 0x2b3d0000)
rw space 12288K, 46% used [0x2b3d0000, 0x2b973808, 0x2b973a00, 0x2bfd0000)
Dynamic libraries:
0x00400000 - 0x0040d000      c:\Program Files\Java\jdk1.5.0_07\bin\java.exe
0x7c920000 - 0x7c9b4000      C:\WINDOWS\system32\ntdll.dll
0x7c800000 - 0x7c91c000      C:\WINDOWS\system32\kernel32.dll
0x77da0000 - 0x77e49000      C:\WINDOWS\system32\ADVAPI32.dll
0x77e50000 - 0x77ee1000      C:\WINDOWS\system32\RPCRT4.dll
0x77be0000 - 0x77c38000      C:\WINDOWS\system32\MSVCRT.dll
0x6d730000 - 0x6d8c7000      c:\Program Files\Java\jdk1.5.0_07\jre\bin\client\jvm.dll
0x77d10000 - 0x77d9f000      C:\WINDOWS\system32\USER32.dll
0x77ef0000 - 0x77f37000      C:\WINDOWS\system32\GDI32.dll
0x76b10000 - 0x76b3a000      C:\WINDOWS\system32\WINMM.dll
0x76300000 - 0x7631d000      C:\WINDOWS\system32\IMM32.DLL
0x62c20000 - 0x62c29000      C:\WINDOWS\system32\LPK.DLL
0x73fa0000 - 0x7400b000      C:\WINDOWS\system32\USP10.dll
0x6d2f0000 - 0x6d2f8000      c:\Program Files\Java\jdk1.5.0_07\jre\bin\hpi.dll
0x76bc0000 - 0x76bcb000      C:\WINDOWS\system32\PSAPI.DLL
0x6d700000 - 0x6d70c000      c:\Program Files\Java\jdk1.5.0_07\jre\bin\verify.dll
0x6d370000 - 0x6d38d000      c:\Program Files\Java\jdk1.5.0_07\jre\bin\java.dll
0x6d720000 - 0x6d72f000      c:\Program Files\Java\jdk1.5.0_07\jre\bin\zip.dll
0x10000000 - 0x10033000      E:\jnis\sample.dll
VM Arguments:
java_command: HelloWorld
Launcher Type: SUN_STANDARD
Environment Variables:
JAVA_HOME=C:\Program Files\Java\jdk1.5.0_07
CLASSPATH=.;.;C:\PROGRA~1\JMF21~1.1E\lib\sound.jar;C:\PROGRA~1\JMF21~1.1E\lib\jmf.jar;C:\PROGRA~1\JMF21~1.1E\lib;
PATH=C:\cygwin\usr\local\bin;C:\cygwin\bin;C:\cygwin\bin;C:\cygwin\usr\X11R6\bin;c:\WINDOWS\system32;c:\WINDOWS;c:\WINDOWS\System32\Wbem;c:\Program Files\Java\jdk1.5.0_07\bin;c:\Program Files\OPENXTRA\Ethereal;c:\Program Files\OPENXTRA\WinDump;d:\Program Files\jProbe\bin;c:\maven-2.0.6-bin\maven-2.0.6\bin;d:\Open Source\apache-ant-1.7.0\bin;d:\swtdlls;d:\Program Files\CVSNT\;c:\Program Files\OPENXTRA\WinPCap
USERNAME=Administrator
OS=Windows_NT
PROCESSOR_IDENTIFIER=x86 Family 15 Model 4 Stepping 9, GenuineIntel
--------------- S Y S T E M ---------------
OS: Windows XP Build 2600 Service Pack 2
CPU:total 1 family 15, cmov, cx8, fxsr, mmx, sse, sse2, ht
Memory: 4k page, physical 515572k(238244k free), swap 1260260k(935080k free)
vm_info: Java HotSpot(TM) Client VM (1.5.0_07-b03) for windows-x86, built on May 3 2006 01:04:38 by "java_re" with MS VC++ 6.0
Java Code like this:
     static{
          try{
               System.loadLibrary("sample");
          }catch(Exception e){
               System.out.println("Can't load sample.dll");
     //Declare native method
     public native void sayHello(String name);
  public static void main(String[] args){
    HelloWorld hw=new HelloWorld();
    hw.sayHello("QUKI");
  }And C code like this:
JNIEXPORT void JNICALL Java_HelloWorld_sayHello
  (JNIEnv *env, jobject obj, jstring s)
     /* Obtain a C-copy of the Java string */
     //printf("Hello,every one");
    const char *str = (*env)->GetStringUTFChars(env, s, 0);
     printf("Java Call C success....%s\n",*str);
}Any one can tell me why??Thanx very much.

Answer 1

const char str = (env)->GetStringUTFChars(env, s, 0);
printf("Java Call C success....%s\n",*str);
Any one can tell me why??Thanx very much.That asterisk(*) in front of str in the printf() statement is dereferencing the variable. Thus it is a char and not a char*. But %s requires a char*.
EXCEPTION_ACCESS_VIOLATION (0xc0000005) Note that when you get the above, with the ...05 error, that it always means you did something incorrect with a pointer somewhere.