Name: boT120536 Date: 11/30/2000


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

This is a very annoying problem when trying to use JNI with j2se1.3 jvm. The
C++ compiler is Sun Workshop 6. Basically this is a code which uses cout to
print "Hello World" to standard output from native code. Here is the code, and
the Makefile used to build it:
Main.java:
#######
//
// Load a native library. Create an object
// and invoke a native method.
//

public class Main {
    public static void main(String[] args) {
        System.loadLibrary("Native");
        AClassWithNativeMethods
            c = new AClassWithNativeMethods();
        c.theNativeMethod();
    }
}
#######
AClassWithNativeMethods.java:
#######
// File: AClassWithNativeMethods.java
// A really simple example of a class containing
// a native method.
public class AClassWithNativeMethods {
    public native void theNativeMethod();
}
######
jniAClassWithNativeMethods.cpp
######
/* File: theNativeMethod.c
 * Implements AClassWithNativeMethods.theNativeMethod
 */
#ifndef MAKEDEPEND
#include <iostream>
#include <cstdio>
#endif
#include "AClassWithNativeMethods.h"
using namespace std;

JNIEXPORT void JNICALL Java_AClassWithNativeMethods_theNativeMethod
        (JNIEnv* env, jobject thisObj) {
            cout << "Hello world!" << endl;
}
########

The header file AClassWithNativeMethods.h is generated by the command:
"javah -jni AClassWithNativeMethods"

The Makefile is as follows:
######
#
# Makefile for example code
#

JNI_LIB = libNative.so

CPP_SOURCES = jniAClassWithNativeMethods.cpp

SOURCES_JAVA = Main.java
SOURCES_NATIVE = AClassWithNativeMethods.java

JAVA_SOURCES = $(SOURCES_JAVA) $(SOURCES_NATIVE)

#
# Sources.h defines $(SOURCES)
#
CLASSES = $(JAVA_SOURCES:.java=.class)
HEADERS_NATIVE = $(SOURCES_NATIVE:%.java=%.h)
OBJECTS = $(CPP_SOURCES:.cpp=.o)
JDK_HOME = $(JAVA_HOME)

#for sun
CCFLAGS = -g -KPIC
LDLIBS = -lm -lCrun -lCstd
LDFLAGS = -G

INCLUDES = -I$(JDK_HOME)/include -I$(JDK_HOME)/include/solaris

.SUFFIXES: .cpp
.cpp.o:
        @echo "# Compiling $@ because of $?:"
        $(COMPILE.cc) $(INCLUDES) $<

.java.class:
        @echo "# Compiling $@ because of $?:"
        $(JDK_HOME)/bin/javac -g $<

%.h:%.class
        @echo "# Creating $@ for class $* because of $?:"
        $(JDK_HOME)/bin/javah -jni $*

default:
        cat Makefile > makefile0
        makedepend -DMAKEDEPEND $(INCLUDES) -fmakefile0 $(CPP_SOURCES)
        make -f makefile0 classes native $(JNI_LIB)

classes: $(CLASSES)

native: $(HEADERS_NATIVE)

$(JNI_LIB): $(OBJECTS)
        @echo "# Linking $@ because of $?."
        $(LINK.cc) $(INCLUDES) $(OBJECTS) -o $@ $(LDLIBS)

clean:
        @echo "# Cleaning up objects:"
        - /bin/rm -f $(CLASSES)
        - /bin/rm -f $(HEADERS_NATIVE)
        - /bin/rm -f $(JNI_LIB)
        - /bin/rm -f $(OBJECTS)

# DO NOT DELETE THIS LINE -- make depend depends on it.
########
I am using /usr/ccs/bin/make.

The output of the code is:
jal@ducati:127>java Main
# # An unexpected exception has been detected in native code outside the VM.#
  Program counter=0xfd2bb22c
#
# Problematic Thread: prio=5 tid=0x280e0 nid=0x1 runnable
#
Abort (core dumped)


The dbx call stack is:


current thread: t@1
  [1] std::basic_ostream<char,std::char_traits<char>
>::sentry::~sentry(0xffbee2d4, 0x0, 0xfd2ebaf4, 0xfd2b8b28, 0xffbee2d4,
0xff0000), at 0xfd2bb22c
  [2] std::operator<<(0xfd2ec668, 0xfd2ec680, 0xfd2ec670, 0xfd2ebaf4, 0x0, 0xc),
at 0xfd2ba0b8
=>[3] Java_AClassWithNativeMethods_theNativeMethod(env = 0x28164, thisObj =
0xffbee42c), line 14 in "jniAClassWithNativeMethods.cpp"
  [4] 0x6fb10(0xf4c34530, 0xffbee518, 0x280e0, 0xfe773b44, 0xb6, 0xf8cb6548), at
0x6fb0f
  [5] 0x6cc94(0x0, 0x1, 0xfe77fd78, 0x75d18, 0x1e, 0xe), at 0x6cc93
  [6] 0xfe7a4994(0xffbee538, 0xffbee738, 0xa, 0xf8cb63c8, 0x6ecdc, 0xffbee66c),
at 0xfe7a4993
  [7] JavaCalls::call_helper(0xffbee730, 0xfe773b44, 0xffbee664, 0x280e0,
0x6ecdc, 0xffbee738), at 0xfe549d3c
  [8] JavaCalls::call(0xffbee730, 0xffbee644, 0xffbee664, 0x280e0, 0xfe773b44,
0xffbee5dc), at 0xfe5499e8
  [9] jni_invoke(0x1, 0x280e0, 0x0, 0x0, 0xe6198, 0xffbee714), at 0xfe551aec
  [10] jni_CallStaticVoidMethod(0x280e0, 0xfe773b44, 0xe6198, 0x28164,
0xffbee798, 0x0), at 0xfe55e15c
  [11] main(0x28164, 0x0, 0x28164, 0xffbef1ef, 0x0, 0x25508), at 0x1212c


So you see it dies in the cout call.
I don't know if this is a jvm problem or a Workshop 6 problem. It doesn't die
when I use the GNU g++ compiler or the KAI KCC compiler for the native code. It
also doesn't die when I use an earlier jvm like java 1.2.
(Review ID: 112266)
======================================================================

Name: yyT116575 Date: 01/23/2001


/app/java/jre/1.3.0_us/bin/java -version

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

Using JNI, we call a C code which is used as an interface to a C++ code. The
C++ code contains cout instructions. With the preceeding version of the
JVM:
/app/java/jre/1.2.2_05a_us/bin/java -version

java version "1.2.2"
Solaris VM (build Solaris_JDK_1.2.2_05a, native threads, sunwjit)

we saw the prints on the console, while with JVM 1.3, all what we've got is

# # An unexpected exception has been detected in native code outside the VM.
# Program counter=0xe01560e0
#
# Problematic Thread: prio=6 tid=0xf3c68 nid=0xb runnable
#
Abort
(Review ID: 115604)
======================================================================