Native call in JCVM

Hi All,
I read the specs of JCVM and i knew that the native keyword is not supported. Hence i am confusing that how the jcvm knows that whether it needs to access to native methods defined in JCRE? I don't see any flag indicating if a method is native in all cap components.
Thank you for your answer,
H. Long

user5138836 wrote:
I assume that the card chip understand C language but not java language.The chip uses native code compiled from C. The chip also understands assembly.
something is masked, it is loaded into ROM. Can it be java byte codes or only C program? Is the term "masked" also understood as "native" concept or only relevant to the type of memory that the item is loaded into?Masking is the process of loading into ROM. It can be anything.
http://en.wikipedia.org/wiki/Mask_ROM
if we can mask byte codes, and i have JCVM masked, written in C then how the JCVM finds out the "masked" byte codes to execute it?
I am concerning about the position in memory to indicate the JCVM jump pointer and load contents.I am not sure of this. I assume the mask would work roughly the same as something loaded onto EEPROM except it has to be there at fabrication time. I could be wrong about this though.
Cheers,
Shane

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please don't forget to rate the helpful posts

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$(MIDP_DIR)/src/share/classes/com/sun/mmedia \
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When I use this interface without a JFrame, simply calling "goToFilter(5)", it works perfectly. When I call it within the ActionListener, it crashes.
* @author Jason Thomas
* @version 1.0
* Test program for the Java interface to my C++ FilterWheel object.
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class FilterWheel
static
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FilterWheel()
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Exception:
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Unexpected Signal : 11 occurred at PC=0x4C85A87F
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Library=/home/jason/FWheel/Bakup/libfilterwheel.so
NOTE: We are unable to locate the function name symbol for the error
just occurred. Please refer to release documentation for possible
reason and solutions.
Current Java thread:
at FilterInterface.goToFilter(Native Method)
at FilterWheel$1.actionPerformed(FilterWheel.java:32)
at javax.swing.JTextField.fireActionPerformed(JTextField.java:489)
at javax.swing.JTextField.postActionEvent(JTextField.java:670)
at javax.swing.JTextField$NotifyAction.actionPerformed(JTextField.java:784)
at javax.swing.SwingUtilities.notifyAction(SwingUtilities.java:1502)
at javax.swing.JComponent.processKeyBinding(JComponent.java:2422)
at javax.swing.JComponent.processKeyBindings(JComponent.java:2457)
at javax.swing.JComponent.processKeyEvent(JComponent.java:2385)
at java.awt.Component.processEvent(Component.java:4830)
at java.awt.Container.processEvent(Container.java:1525)
at java.awt.Component.dispatchEventImpl(Component.java:3526)
at java.awt.Container.dispatchEventImpl(Container.java:1582)
at java.awt.Component.dispatchEvent(Component.java:3367)
at java.awt.KeyboardFocusManager.redispatchEvent(KeyboardFocusManager.java:1700)
at java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(DefaultKeyboardFocusManager.java:568)
at java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(DefaultKeyboardFocusManager.java:740)
at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(DefaultKeyboardFocusManager.java:673)
at java.awt.DefaultKeyboardFocusManager.dispatchEvent(DefaultKeyboardFocusManager.java:534)
at java.awt.Component.dispatchEventImpl(Component.java:3396)
at java.awt.Container.dispatchEventImpl(Container.java:1582)
at java.awt.Window.dispatchEventImpl(Window.java:1581)
at java.awt.Component.dispatchEvent(Component.java:3367)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:445)
at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:191)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:144)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:138) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:130) at java.awt.EventDispatchThread.run(EventDispatchThread.java:98)
Dynamic libraries:
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4002c000-40039000 r-xp 00000000 03:05 245766 /lib/i686/libpthread-0.10.so
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4cdb2000-4cdba000 r-xp 00000000 03:05 328592 /usr/X11R6/lib/libSM.so.6.0
4cdba000-4cdbb000 rw-p 00007000 03:05 328592 /usr/X11R6/lib/libSM.so.6.0
4cdbb000-4cdcf000 r-xp 00000000 03:05 328550 /usr/X11R6/lib/libICE.so.6.3
4cdcf000-4cdd0000 rw-p 00013000 03:05 328550 /usr/X11R6/lib/libICE.so.6.3
4cdd2000-4ce97000 r-xp 00000000 03:05 348471 /usr/java/j2sdk1.4.0_01/jre/lib/i386/libfontmanager.so
4ce97000-4ceb1000 rw-p 000c4000 03:05 348471 /usr/java/j2sdk1.4.0_01/jre/lib/i386/libfontmanager.so
4cf54000-4cf70000 r-xp 00000000 03:05 510718 /usr/X11R6/lib/X11/locale/common/ximcp.so.2
4cf70000-4cf72000 rw-p 0001b000 03:05 510718 /usr/X11R6/lib/X11/locale/common/ximcp.so.2
Local Time = Thu Feb 13 15:49:51 2003
Elapsed Time = 8
# The exception above was detected in native code outside the VM
# Java VM: Java HotSpot(TM) Client VM (1.4.0_01-b03 mixed mode)
# An error report file has been saved as hs_err_pid2843.log.
# Please refer to the file for further information.
Any help would be greatly appreciated.
-Jason Thomas.

Gdb's trace of the cause of all of my problems:
Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 90124 (LWP 11810)]
0x4c85a89f in outb () from /home/jason/FWheel/libfilterwheel.so
This is what I get from the debugger. I'm using the function outb to write to the parallel port address 0x378, which I've used the function ioperm to permit read/write access to. The program works just fine if I call the "stepFilter" function (that calls outb) outside of the ActionListener's actionPerfomed method. Like if I'm probing for keboard input inside the constructor:
* @author Jason Thomas
* @version 1.0
* Test program for the Java interface to my C++ FilterWheel object.
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
public class FilterWheelTest
static
     System.loadLibrary("filterwheel");
FilterWheelTest()
     BufferedReader myReader = new BufferedReader(new InputStreamReader(System.in));
     String inString;
     try
     while((inString = myReader.readLine()) != null)
          myWheel.goToFilter(Integer.parseInt(inString));
     myWheel._delete();
     catch(IOException e)
     e.printStackTrace();
     System.exit(-1);
public static void main(String args[])
     new FilterWheelTest();
The program above works fine, the one I posted previously does not. The only difference is that the one I first posted is inside of an ActionListener, and this one is not.
-Jason Thomas.

Native call in Servlet crashing tomcat

I can execute the class from the unix prompt (invoking the main) and it works fine, however when I invoke it withing a servlet or jsp, i get a core dump.
It seems to be a treading issue. I am including the tread dump of ONLY the thread that died.
Any advice on getting this going would be appreciated.
Derek
SIGSEGV 11* segmentation violation
si_signo [11]: SIGSEGV 11* segmentation violation
si_errno [0]:
si_code [2]: SEGV_ACCERR [addr: 0x0]
stackpointer=ba12a2d4
Full thread dump Classic VM (Caldera-UNIX-J2SE-1.3.0_02:*fixes-OU8*fixes-UW7*FCS-OSR5*:020322-03:47, native threads):
"Thread-9" (TID:0xbca3aa50, sys_thread_t:0x83e7738, state:R, native ID:0xe) prio=5
at JavaToCPageInterface.sendMessage(Native Method)
at doit_3._jspService(doit_3.java, Compiled Code)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:119)
at javax.servlet.http.HttpServlet.service(HttpServlet.java)
at org.apache.tomcat.facade.ServletHandler.doService(ServletHandler.java, Compiled Code)
at org.apache.tomcat.core.Handler.invoke(Handler.java:322)
at org.apache.tomcat.core.Handler.service(Handler.java, Compiled Code)
at org.apache.tomcat.facade.ServletHandler.service(ServletHandler.java:485)
at org.apache.tomcat.core.ContextManager.internalService(ContextManager.java, Compiled Code)
at org.apache.tomcat.core.ContextManager.service(ContextManager.java, Compiled Code)
at org.apache.tomcat.modules.server.Http10Interceptor.processConnection(Http10Interceptor.java, Compiled Code)
at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java, Compiled Code)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java, Compiled Code)
at java.lang.Thread.run(Thread.java:484)

More Info:
j2sdk 1.3.1
Tomcat 3
The program executes fine as a stand-along app, however if it is called from withing a servlet or JSP, Tomcat core dumps.
Have tried -Xss10m as a parameter, however it does not work. I have also tried both green and native threads.
Thanks,
Derek

Problem including: thread, native calls, web service

I have the following problem:
There is web service (myService) running on a 2-processor machine
The web service starts a thread (myThread)
The thread's run calls a native method (myNative).
The implementation of the native method simply calls a function (myFunc).
The web service starts the thread and waits for it to end (with join() ).
The above are summarized in the following:
myService
myThread.run()
myNative()
myFunc()
The problem is:
it seems that while myThread has ended its execution, the myNative function keeps running.
(e.g. messages of myNative are printed after the end of the execution of myThread)
Could this be related to the fact that the machine has 2 processors?
What could be the cause?
Thank you in advance.

This is most likely caused by how the native processes standard output streams are implemented. Try using some other form of feedback (i.e. write to a file, or throw up a user dialog box) and you'll most likely see that the native method is indeed returning when you think it should, but the native output stream doesn't show up until later.
- K

Crash in native calls to MAPI

Hi All
In the application that we are developing, we have java wrapper over Micosoft MAPI calls to integrate with MS Exchange Server. Our Application can be run in two modes (local and remote). In local configurations, all the calls are in the same JVM. In the remote configuration, our application will be deployed in a tomcat and we use jUnit test cases (running on another JVM) to test it. Our application exposes webservices from tomcat.
The problem we are facing is inconsistent crashes when configured in remote mode. However, we don't see the crashes happening in the local configuration. Any pointers would be of great help!
-Abhi

Hi,
Developers can also use j-XChange (http://sourceforge.net/projects/j-xchange/). It is a pure Java implementation of the entire Collaboration Data Objects (CDO 1.21) library, offered under LGPL license and allows interoperability with MS Exchange from all non-Windows platforms that support Java. This library is powered by j-Interop (www.j-interop.org).
This library is functionally similar to Commercial "J-Integra for Exchange" offering.
Thanks,
best regards,
Vikram

Native call in JCVM

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