ID: Q162164
The information in this article applies to:
There are various problems that you may experience when you try to use an Automation Server written in Java as a DCOM server. These can include hanging, timeouts, out of memory errors, interface not found errors, and other errors. These errors are generally caused by not registering the Java COM object properly on both the client and DCOM server machines. There are several known bugs with the javareg DCOM surrogate and the DCOM configuration utility DCOMCNFG that make it difficult to set up Java DCOM servers and clients.
Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. We are researching this bug and will post new information here in the Microsoft Knowledge Base as it becomes available.
This article explains how to use the COMCallingJava sample shipped with Visual J++ 1.0 and 1.1 as a DCOM server.
First you should build the sample and run it as a conventional (InProcess) automation server. Do this by following the instructions outlined in the readme.html that is installed with the sample. Once you have the sample running normally, use the following steps to use the sample via DCOM.
NOTE: The DCOM support now in Windows 95 and Windows NT 4.0 with Service Pack 2 and Service Pack 3 supports surrogate as part of the system, so the surrogate support with JavaReg1.0 has been dropped. JavaReg2.0 is a new tool that ships with the Microsoft SDK for Java 2.0 and later. This tool fixes the bugs associated with JavaReg1.0 and supports remote access to a Java/COM object using the system provided surrogate process. There is also a Knowledge Base article listed in the REFERENCES section below that discusses the use of DllSurrogate.
Follow these steps on the client machine so that you can use the COMCallingJava sample via DCOM:
1. Run Javatlb (or JactiveX, then compile the resulting wrapper classes
with jvc.exe)on the client in order to generate the registry entries for
the COM Interfaces (the IGCD interface for this sample).
3. Run DCOMCNFG to select the DCOM Server machine.
4. Delete the InprocServer32 key created in step 2.
More detailed information on these 4 steps:
1. On the client side, you need to register both the CEuclid CoClass object
and the IGCD interface. The IGCD interface can be registered by running
JavaTLB.exe (or JActiveX.exe)on the euclid.tlb OLE type library file
produced by building the ComCallingJava sample program as described in
the readme.html supplied with the sample. To register the interfaces, on
the client machine, run:
JAVATLB EUCLID.TLB
This registers the IGCD interface and produces a euclid package in
\winnt\java\trustlib that contains the CEuclid.class and IGCD.class COM
class wrapper files. This package is not required on the client machine
and can be safely deleted by deleting the euclid directory.
NOTE: If you are using JActiveX.exe, you'll also need to compile the
resulting Java source files in the appropriate <windir>\java\trustlib\
directory.
with Visual J++. Run the following command line on the client machine
to register the CEuclid class on the client:
javareg /register /class:CEuclid /clsid:{33B0ECE2-E706-11cf-A0C2-
00AA00A71DD8}
should be created on a seperate machine, and specify the machine on
which it should be created. This can be done with the DCOMCNFG utility
that is included with Windows NT 4.0 and the Windows 95 DCOM beta. Run
the DCOMCNFG utility by clicking Run on the Start menu, typing in
DCOMCNFG, and clicking OK. On the Applications tab of the DCOMCNFG
utility, you should find an entry for CEuclid - "Java Class: CEuclid".
Select this entry and click Properties. In the dialog box that appears,
select the Location tab. In the Location tab, select the "Run
application on the following computer" and type the name of the
computer that will be the DCOM server.
with the DCOMCNFG utility. The DCOMCNFG utility should, but does not,
remove the InprocServer32 reg key that indicates that the Java COM
object should be run as an In Process dll. You can manually delete this
key by running REGEDIT and locating the
HKEY_CLASSES_ROOT\CLSID\{33B0ECE2-E706-11cf-A0C2-00AA00A71DD8} folder.
This folder should contain a subfolder called InprocServer32. Select
the InprocServer32 subfolder and delete it and all of its contents. Be
very careful when manually editing the registry. Deleting the wrong key
can make your system nonfunctional.
<<<<<<<<<<<<<<<<start of client side reg file>>>>>>>>>>>>>>>>>
REGEDIT4
[HKEY_CLASSES_ROOT\AppID\{33B0ECE2-E706-11cf-A0C2-00AA00A71DD8}]
@="Java Class: CEuclid"
"RemoteServerName"="MYSERVER"
[HKEY_CLASSES_ROOT\CLSID\{33B0ECE2-E706-11cf-A0C2-00AA00A71DD8}]
@="Java Class: CEuclid"
"AppID"="{33B0ECE2-E706-11cf-A0C2-00AA00A71DD8}"
[HKEY_CLASSES_ROOT\CLSID\{33B0ECE2-E706-11cf-A0C2-
00AA00A71DD8}\Implemented Categories]
[HKEY_CLASSES_ROOT\CLSID\{33B0ECE2-E706-11cf-A0C2-
00AA00A71DD8}\Implemented Categories\{BE0975F0-BBDD-11CF-97DF-
00AA001F73C1}]
[HKEY_CLASSES_ROOT\Interface\{33B0ECE1-E706-11CF-A0C2-00AA00A71DD8}]
@="IGCD"
[HKEY_CLASSES_ROOT\Interface\{33B0ECE1-E706-11CF-A0C2-
00AA00A71DD8}\ProxyStubClsid]
@="{00020420-0000-0000-C000-000000000046}"
[HKEY_CLASSES_ROOT\Interface\{33B0ECE1-E706-11CF-A0C2-
00AA00A71DD8}\ProxyStubClsid32]
@="{00020420-0000-0000-C000-000000000046}"
To use this file, copy the text to notepad and save it as CEuclidClient.reg. Double-click CEuclidClient.reg from the client machine to import the registry entries into the client machine registry. Note that this sample reg file has the "RemoteServerName" key set to "MYSERVER" (this entry is created by dcomcnfg). You can either change the MYSERVER text to the name of your DCOM server, or use the DCOMCNFG utility on the client machine to change the DCOM server name after importing the reg file.
You need to follow these steps on the DCOM server machine in order to use the COMCallingJava sample via DCOM. Note that the Java VM must be installed on the Server machine in order to use a Java class file as a DCOM object. The latest Java VM can be downloaded from http://www.microsoft.com/java.
1. Copy the CEuclid.class file generated by Jvc.exe to the Server machines
java\trustlib directory.
with jvc.exe)on the Euclid.tlb file on the server machine to generate
the Java COM wrapper files as well as register the Java COM objects COM
Interfaces.
file as a COM object, as well as create the registry entries needed
to use Javareg.exe as the DLL Surrogate EXE.
to "Apartment" threading.
1. On the DCOM server, first you need to copy the CEuclid.class file
that is generated by the Visual J++ compiler (Jvc.exe) to the Server
machine trusted classpath - "\winnt\java\trustlib". Note that after
building the COMCallingJava sample, there will be two CEuclid.class
files on your build machine - One in the COMCallingJava project folder
and one in the \windows\java\trustlib\euclid directory. The version of
CEuclid.class in the project folder (the one generated by Jvc.exe) is
the one that is the actual implementation of the Java COM object. This
is the one that you want to copy to the \winnt\java\trustlib directory.
The other version is generated by Javatlb.exe from the OLE type library
(step 2) and contains special class file attributes that indicate to
the VM that this java class is actually implemented in a COM/ActiveX
object.
Javareg.exe, and Euclid.tlb. Javatlb.exe and Euclid.tlb are needed
temporarily in order to register the Java COM object. Javareg.exe will
be needed on the DCOM server machine semi-permanently. Javareg.exe, in
addition to creating registry entries needed to register a Java COM
object, can also be used as a "DLL Surrogate" executable. EXE servers
are the only type that can be used via DCOM. The DLL Surrogate is an
EXE that can be used to load an In-Process ActiveX/COM DLL (i.e., the
Java VM) and marshall the COM calls cross-process and via DCOM, cross-
machine. Please note that Javareg.exe is a temporary DLL Surrogate
which will be superceded in the near future by a DLL Surrogate built
into the operating system. This article will be updated with
information on using the OS DLL Surrogate as soon as more information
is available.
Run Javatlb.exe (or JActiveX.exe, then compile the resulting wrapper
classes with jvc.exe)on the Euclid.tlb type library:
JAVATLB EUCLID.TLB
This will (as was described for the client machine) generate a euclid
Java package in the \winnt\java\trustlib directory. Note that the
euclid package - the \winnt\java\trustlib\euclid\IGCD.class and
\winnt\java\trustlib\euclid\CEuclid.class are required on the DCOM
server machine. Do not delete them (you could have deleted them on the
client machine).
directory as a Java COM object. Note the addition of the /surrogate
switch which will register Javareg.exe as the DLL Surrogate:
javareg.exe /register /surrogate /class:CEuclid
clsid:{33B0ECE2-E706-11cf-A0C2-00AA00A71DD8}
surrogate are not correct. You need to run REGEDIT again on the DCOM
Server machine to change the threading model flag. Locate the
InprocServer32 key:
HKEY_CLASSES_ROOT\CLSID\{33B0ECE2-E706-11cf-A0C2-
00AA00A71DD8}\InprocServer32
Note that all of the registry modifications can be done with a setup program, or by importing a .reg file. You will still need to make sure that the CEuclid.class file that was created by Jvc.exe is copied to the java\trustlib directory (step 1). And that the euclid package created by JAVATLB.exe (or JActiveX.exe)exists. Here is a sample reg file that can be utilized on the DCOM server machine to enable the use of the COMCallingJava automation server via DCOM (Note that the explicit path to Javareg.exe in the LocalServer32 key below may need to be changed depending upon where you have copied Javareg.exe to on your DCOM Server machine):
<<<<<<<<<<<<<<<<start of server side reg file>>>>>>>>>>>>>>>>>>
REGEDIT4
[HKEY_CLASSES_ROOT\AppID\{33B0ECE2-E706-11cf-A0C2-00AA00A71DD8}]
@="Java Class: CEuclid"
[HKEY_CLASSES_ROOT\CLSID\{33B0ECE2-E706-11cf-A0C2-00AA00A71DD8}]
@="Java Class: CEuclid"
"AppID"="{33B0ECE2-E706-11cf-A0C2-00AA00A71DD8}"
[HKEY_CLASSES_ROOT\CLSID\{33B0ECE2-E706-11cf-A0C2-
00AA00A71DD8}\Implemented Categories]
[HKEY_CLASSES_ROOT\CLSID\{33B0ECE2-E706-11cf-A0C2-
00AA00A71DD8}\Implemented Categories\{BE0975F0-BBDD-11CF-97DF-
00AA001F73C1}]
[HKEY_CLASSES_ROOT\CLSID\{33B0ECE2-E706-11cf-A0C2-
00AA00A71DD8}\InprocServer32]
@="msjava.dll"
"ThreadingModel"="Apartment"
"JavaClass"="CEuclid"
[HKEY_CLASSES_ROOT\CLSID\{33B0ECE2-E706-11cf-A0C2-
00AA00A71DD8}\LocalServer32]
@="c:\\program files\\devstudio\\vj\\bin\\JAVAREG.EXE /clsid:{33B0ECE2-
E706-11cf-A0C2-00AA00A71DD8} /surrogate"
[HKEY_CLASSES_ROOT\Interface\{33B0ECE1-E706-11CF-A0C2-00AA00A71DD8}]
@="IGCD"
[HKEY_CLASSES_ROOT\Interface\{33B0ECE1-E706-11CF-A0C2-
00AA00A71DD8}\ProxyStubClsid]
@="{00020420-0000-0000-C000-000000000046}"
[HKEY_CLASSES_ROOT\Interface\{33B0ECE1-E706-11CF-A0C2-
00AA00A71DD8}\ProxyStubClsid32]
@="{00020420-0000-0000-C000-000000000046}"
You should now be able to run the Vbdriver.exe sample program installed with the COMCallingJava sample application on the client machine and have the CEuclid Java COM object run on the DCOM server machine (Use the Windows NT Task Manager to view the startup and shutdown of the Javareg DLL surrogate on the Server machine).
For additional information on using the DllSurrogate support for Java/DCOM servers, please refer to the following Knowledge Base article:
ARTICLE-ID: Q173790
TITLE: HOWTO: Using DllSurrogate Support for Java/DCOM
servers.
http://support.microsoft.com/support/visualj/
http://support.microsoft.com/support/java/
Keywords : kbtool kbGenInfo kbVJ kbVJ100bug kbVJ110bug JCOM
Version : 1.0 1.1
Platform : WINDOWS
Issue type : kbbugLast Reviewed: November 15, 1998