JSP Call C Library through JNI ?

Hi experts :
I has a jsp file which create a bean to call native c method.
It still works fine after 10 to 14 times' page refresh, then
it throws exception when call a native method.
If I restart the Tomcat it works again ,but shuch situtation repeat again.
Should I notice any issues when access native c library
through JNI in jsp ?
Environment:
SPARC 64 Solaris 7
Tomcat 4.0.4
JDK 1.3.1-04

hi CTSteven
Did you find a solution for this JNI-Problem ? I think i have the same problem as you. Would be great to here from you.
Thank you.
Bye
Lukas

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I have a C++ code that executes a method inside the jvm through the JNI.
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Java.lang.Class- getFields() results in JVM crash when called through JNI

From a C++ application, I use Invocation APIs to create a JVM and call some Java methods using JNI
I get a crash in jvm.dll with EXCEPTION_ACCESS_VIOLATION
when I try to call "getFields" method of java.lang.Class in order to get the Fields of the java class
This method call, should return a java/lang/reflect/Fields[] on success
I am able to get the method ID of this method by using pEnv->GetMethodID(..)
However, when I call this method using CallObjectMethod(..), HotSpt JVM crashes with access violation with the dump given below.
Any clues on how to debug and find the problem?
Or has anyone tried getting the fields of a Java class from C++ by calling reflection APIs uing JNI?
Thanks in advance!
Sample code
jclass testerClass = pEnv->FindClass("com/test/Tester");
jmethodID cid = pEnv->GetMethodID(testerClass,"<init>","()V");
if(NULL == cid)
pEnv->ExceptionDescribe();
jobject testerObject = pEnv->NewObjectV(testerClass, mid);
jmethodID mid = pEnv->GetMethodID(testerClass, "getClass",
 "()Ljava/lang/Class;");
jobject clsObj = (jobject)pEnv->CallObjectMethod(testerObject, mid);
pEnv->ExceptionDescribe();
jclass jCls = pEnv->GetObjectClass(clsObj);
jmethodID midGetFields = pEnv->GetMethodID(jCls, "getFields",
 "()[Ljava/lang/reflect/Field;");
jobjectArray jobjArray = (jobjectArray)pEnv->CallObjectMethod(testerObject, midGetFields);
pEnv->ExceptionDescribe();
Crash dump
Unexpected Signal : EXCEPTION_ACCESS_VIOLATION (0xc0000005) occurred at PC=0x809E69F
Function=JVM_FindSignal+0x11505
Library=D:\Java\j2re1.4.2_03\bin\client\jvm.dll
Current Java thread:
 at java.lang.Class.privateGetDeclaredFields(Unknown Source)
 at java.lang.Class.privateGetPublicFields(Unknown Source)
 at java.lang.Class.getFields(Unknown Source)
Dynamic libraries:
0x00400000 - 0x00419000 E:\SC\SC12.1\SCApplications\SNMP\Bin\JNITester.exe
0x77F50000 - 0x77FF7000 C:\WINDOWS\System32\ntdll.dll
0x77E60000 - 0x77F46000 C:\WINDOWS\system32\kernel32.dll
0x10000000 - 0x10023000 E:\SC\SC12.1\SCApplications\SNMP\Bin\JniUtils.dll
0x00320000 - 0x00332000 E:\SnmpIpmNativeTestDriver\MTFStubHelper.dll
0x00340000 - 0x0035B000 E:\SnmpIpmNativeTestDriver\MTFXMLFileAPI.dll
0x12000000 - 0x122B1000 e:\sc\sc12.1\bin\xerces-c_2_2_0D.dll
0x77DD0000 - 0x77E5D000 C:\WINDOWS\system32\ADVAPI32.dll
0x78000000 - 0x78086000 C:\WINDOWS\system32\RPCRT4.dll
0x10200000 - 0x1026C000 e:\sc\sc12.1\bin\MSVCRTD.dll
0x102A0000 - 0x102B7000 e:\sc\sc12.1\bin\MSVCIRTD.dll
0x5F800000 - 0x5F8E9000 e:\sc\sc12.1\bin\MFC42uD.DLL
0x77C70000 - 0x77CB0000 C:\WINDOWS\system32\GDI32.dll
0x77D40000 - 0x77DCC000 C:\WINDOWS\system32\USER32.dll
0x5F700000 - 0x5F746000 e:\sc\sc12.1\bin\MFCD42uD.DLL
0x5F500000 - 0x5F5C6000 e:\sc\sc12.1\bin\MFCO42uD.DLL
0x10480000 - 0x104FE000 e:\sc\sc12.1\bin\MSVCP60D.dll
0x15020000 - 0x15042000 e:\sc\sc12.1\bin\SCTraceLib.dll
0x6D510000 - 0x6D58D000 C:\WINDOWS\System32\dbghelp.dll
0x77C10000 - 0x77C63000 C:\WINDOWS\system32\msvcrt.dll
0x77C00000 - 0x77C07000 C:\WINDOWS\system32\VERSION.dll
0x00360000 - 0x0037D000 e:\sc\sc12.1\bin\SCFileManager.dll
0x76BF0000 - 0x76BFB000 C:\WINDOWS\System32\PSAPI.DLL
0x00420000 - 0x00580000 e:\sc\sc12.1\bin\BctCoreCL.dll
0x5D920000 - 0x5D929000 C:\WINDOWS\System32\RPCNS4.dll
0x71B20000 - 0x71B31000 C:\WINDOWS\system32\MPR.dll
0x71C20000 - 0x71C6E000 C:\WINDOWS\System32\NETAPI32.dll
0x71AB0000 - 0x71AC5000 C:\WINDOWS\System32\WS2_32.dll
0x71AA0000 - 0x71AA8000 C:\WINDOWS\System32\WS2HELP.dll
0x15000000 - 0x15012000 e:\sc\sc12.1\bin\CTEventLog.dll
0x773D0000 - 0x77BC2000 C:\WINDOWS\system32\SHELL32.dll
0x70A70000 - 0x70AD4000 C:\WINDOWS\system32\SHLWAPI.dll
0x771B0000 - 0x772D1000 C:\WINDOWS\system32\ole32.dll
0x77120000 - 0x771AB000 C:\WINDOWS\system32\OLEAUT32.dll
0x1F7A0000 - 0x1F7D6000 C:\WINDOWS\System32\ODBC32.dll
0x77340000 - 0x773CB000 C:\WINDOWS\system32\COMCTL32.dll
0x763B0000 - 0x763F5000 C:\WINDOWS\system32\comdlg32.dll
0x08000000 - 0x08138000 D:\Java\j2re1.4.2_03\bin\client\jvm.dll
0x76B40000 - 0x76B6C000 C:\WINDOWS\System32\WINMM.dll
0x5FD00000 - 0x5FD0D000 C:\WINDOWS\System32\MFC42LOC.DLL
0x71950000 - 0x71A34000 C:\WINDOWS\WinSxS\x86_Microsoft.Windows.Common-Controls_6595b64144ccf1df_6.0.10.0_x-ww_f7fb5805\comctl32.dll
0x1F840000 - 0x1F857000 C:\WINDOWS\System32\odbcint.dll
0x5DAC0000 - 0x5DAC7000 C:\WINDOWS\System32\rdpsnd.dll
0x00FE0000 - 0x00FE7000 D:\Java\j2re1.4.2_03\bin\hpi.dll
0x01000000 - 0x0100E000 D:\Java\j2re1.4.2_03\bin\verify.dll
0x01010000 - 0x01029000 D:\Java\j2re1.4.2_03\bin\java.dll
0x01030000 - 0x0103D000 D:\Java\j2re1.4.2_03\bin\zip.dll
0x76C90000 - 0x76CB2000 C:\WINDOWS\system32\imagehlp.dll
Heap at VM Abort:
Heap
def new generation total 576K, used 132K [0x15050000, 0x150f0000, 0x15530000)
eden space 512K, 25% used [0x15050000, 0x15071250, 0x150d0000)
from space 64K, 0% used [0x150d0000, 0x150d0000, 0x150e0000)
to space 64K, 0% used [0x150e0000, 0x150e0000, 0x150f0000)
tenured generation total 1408K, used 0K [0x15530000, 0x15690000, 0x19050000)
the space 1408K, 0% used [0x15530000, 0x15530000, 0x15530200, 0x15690000)
compacting perm gen total 4096K, used 964K [0x19050000, 0x19450000, 0x1d050000)
the space 4096K, 23% used [0x19050000, 0x191410e0, 0x19141200, 0x19450000)
Local Time = Wed Aug 25 21:06:44 2004
Elapsed Time = 0
# HotSpot Virtual Machine Error : EXCEPTION_ACCESS_VIOLATION
# Error ID : 4F530E43505002EF
# Please report this error at
# http://java.sun.com/cgi-bin/bugreport.cgi
# Java VM: Java HotSpot(TM) Client VM (1.4.2_03-b02 mixed mode)

You are right, I tried getting the java.lang.Class reference for the com.test.Tester by calling getClass() on com.test.Tester
And using this jclass reference for java.lang.Class, I tried getting the method ID of getFields and eventually the Field[]
Thanks for the help
I have some more questions.
Assumption - Using JNI, I got the fields array of com.test.Tester and I am iterating through the fields
1.Assuming that the Tester class had an Integer field say m_nIntVal, then once I get the jobject equivalent of this Field in C++.
Now I need to get the type of the field (I call the method java.lang.reflect.getType() from JNI)
This gives me a jclass reference to it's type i.e java.lang.Integer
2.I need to get the name of this type i.e I want to get the name of the type in a string as "java.lang.Integer"
For this, on the jclass reference of java.lang.Integer got in Step 1, I call getClass() from JNI (to get the java.lang.Class) and then getName()
Now, for calling getClass(), I need a temporary object reference corresponding to the jclass of java.lang.Integer, The problem is that Integer does not have a default constructor, so my call to create the jobject fails.
But, since I do not know that I am constructing an Integer (remember that is what I am trying to find out - getType), I cant pass any values to constructor
Now, how do I go about creating a jobject of Integer, without knowing that I am constructing that, as this does not have a default constructor without parameters
Also, I tried using AllocObject to get the jobject and then tried to get the method ID of getClass(). Even this failed
3. If the com.test.Tester class had a primitive "int" field, say m_nPrimitiveInt
for which java provides a Class representation, I am able to get the jclass reference to the type of m_nPrimitiveInt
Now, how do I get the name of the type as "int" in a string?
Forllowing a similar procedure like in Step 2 fails when I try to pass the jclass reference to the type of m_nPrimitiveInt to the GetMethodID
with the error FATAL ERROR in native method: JNI received a class argument that is not a class
Can you tell me what is the way out?
Thanks in advance,
Also, can I mail you with some doubts that I have? If its ok, please contact me at [email protected]

How can I call remote ejb through jsp?(null)

Trying the code:
 <%@ page import="si3.*,javax.ejb.*,javax.naming.*,java.util.*,java.rmi.RemoteException" %>
 <%
 int h=8;
 int w=8;
 Hashtable p = new Hashtable ();
 p.put(Context.INITIAL_CONTEXT_FACTORY,"weblogic.jndi.WLInitialContextFactory");
 p.put(Context.PROVIDER_URL,"t3://192.168.0.203:7001");
 Context ctx= new InitialContext(p);
 Object homeref = ctx.lookup("si3.test");
 addHome home = (addHome) PortableRemoteObject.narrow(homeref, addHome.class);
 add the_ejb = home.create();
 out.println(the_ejb.add(h,w));
 out.println("adf");
 the_ejb.remove();
 %>
 yzj wrote:
 > I have two server running weblogic5.1.
 > If the jsp and ejb locate the same server running weblogic 5.1 ,works well .But one deploys the ejb (jndi name si3.test),the other runs the jsp.I use jsp call the remote ejb ,catch exception :
 >
 > GMT+08:00 2000:<E> <ServletContext-General> Root
 > > cause of ServletException
 > > javax.naming.NameNotFoundException: 'si3.test'; remaining name 'si3.test'
 > > at
 > > weblogic.jndi.toolkit.BasicWLContext.resolveName(BasicWLContext.java,
 > > Compiled Code)
 > > at
 > > weblogic.jndi.toolkit.BasicWLContext.lookup(BasicWLContext.java:133)
 > > at
 > > weblogic.jndi.toolkit.BasicWLContext.lookup(BasicWLContext.java:574)
 > > at javax.naming.InitialContext.lookup(InitialContext.java:349)
 > > at jsp_servlet.client._jspService(client.java:90)
 > > at weblogic.servlet.jsp.JspBase.service(JspBase.java:27)
 > > at
 > > weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java
 > > :124)
 > > at
 > > weblogic.servlet.internal.ServletContextImpl.invokeServlet(ServletContextImp
 > > l.java:744)
 > > at
 > > weblogic.servlet.internal.ServletContextImpl.invokeServlet(ServletContextImp
 > > l.java:692)
 > > at
 > > weblogic.servlet.internal.ServletContextManager.invokeServlet(ServletContext
 > > Manager.java:
 > > 251)
 > > at
 > > weblogic.socket.MuxableSocketHTTP.invokeServlet(MuxableSocketHTTP.java:363)
 > > at
 > > weblogic.socket.MuxableSocketHTTP.execute(MuxableSocketHTTP.java:263)
 > > at weblogic.kernel.ExecuteThread.run(ExecuteThread.java, Compiled
 > > Code)
 >
 > Why? Can you help me? Thanks.
 > The jsp's source(Client.jsp ):
 > <%@ page import="si3.*,javax.ejb.*,javax.naming.*,java.util.*,java.rmi.RemoteException" %>
 > <%
 > int h=8;
 > int w=8;
 > Hashtable p = new Hashtable ();
 > p.put(Context.INITIAL_CONTEXT_FACTORY,"weblogic.jndi.WLInitialContextFactory");
 > p.put(Context.PROVIDER_URL,"t3://192.168.0.203:7001");
 > Context ctx= new InitialContext(p);
 > addHome home = (addHome) ctx.lookup("si3.test");
 > add the_ejb = home.create();
 > out.println(the_ejb.add(h,w));
 > out.println("adf");
 > the_ejb.remove();
 > %>
 >
 >
 [att1.html]

Deploying a WAR file containing .jsp and servlets (also uses JNI)

Deploying a WAR file containing .jsp and servlets (also uses JNI) on Windows 2000
We had problems making it initially work on Sun ONE Web Server 6.0 Service Pack 1 because of lack of good iPlanet Web
Server documentation on deploying such files.
This is how we went about it:
1) Make one of the servlet and JSP (must call another Java Class) web application (.war) examples work with iPlanet Web
Server.
C:\iPlanet\Servers\plugins\servlets\examples\web-apps\HelloWorld\HelloWorld.war
and
C:\iPlanet\Servers\plugins\servlets\examples\web-apps\jakarta-examples\jarkarta-examples.war
a) Go to your Web Server Administration to deploy the application using GUI Web Application Deploy.
(We usually use command line, we experienced some issues with the GUI version, but maybe it is fixed in the new Web Server
service packs)
From browser, open http://yourserver:8888/
Click on Select a Server:Manage
Click on Virtual Server Class
Click on https-yourserver
Click on the Web Applications Tab
Then, click on Deploy Web Application
Enter the following -
WAR File On: Local
WAR File Path: C:\iPlanet\Servers\plugins\servlets\examples\web-apps\jakarta-examples\jarkarta-examples.war
Application URI: /jakarta
Installation Directory: c:\iPlanet\examples\jakarta-examples
By clicking on OK it deployed the application.
I can verify that it is deployed by selecting "Edit Web Applications" and I see the following entry:
Edit /jakarta c:/iPlanet/examples/jakarta-examples
Also, c:/iPlanet/examples/jakarta-examples should have the similar following directory structure ..
- [images]
- [jsp]
- index.html
- [servlets]
- [META-INF]
- [WEB-INF]
- [classes]
- [tlds]
- web.xml
- index.html
I restarted the server and accessed it using the following URL from my IE browser:
http://yourserver/jakarta/index.html
Then I clicked on the JSP Examples and tried some JSP examples.
b) Alternatively, you can also deploy the same example from the command-line.
Make sure C:\iPlanet\Servers\bin\https\httpadmin\bin\ is in your path
wdeploy deploy -u /jakarta
 -i yourserver
 -v https-yourserver
 -d c:\iplanet\examples\jakarta-examples
 C:\iPlanet\Servers\plugins\servlets\examples\web-apps\jakarta-examples\jarkarta-examples.war
Restart the web server (I don't think you have to restart, but .. might as well).
2)Deploy your web-application
My Foo.war has the following structure.
You can use jar tf Foo.war to look at the file contents from command line (assuming you have JDK installed and the bin is
in your PATH)
Foo.war
- [META-INF]
- [WEB-INF]
- web.xml
- [classes]
- Bar.class
- MoServlet.class
- [lib]
- ThirdParty.jar
- [natlib]
- extlib.dll
- foo.jsp
Here is our application scenario:
foo.jsp uses a class call Bar (it is not in any package). The Bar java class uses classes from ThirdParty.jar. The
ThirdParty.jar in turn uses JNI to load library extlib.dll. foo.jsp also calls /servlet/Mo as well.
Now to deploy it, do the following:
(a) Make sure that within foo.jsp, you import the Bar class ( I don't know why you have to do it, but if you don't you get
JSP compile error).
<%@page language="java" import="Bar" contentType="text/html"%>
(b) Check web.xml (for Servlets)
Within web.xml, make sure you have the following mappings:
<servlet>
<servlet-name> MoLink </servlet-name>
<servlet-class> MoServlet </servlet-class>
</servlet>
<servlet-mapping>
<servlet-name> MoLink </servlet-name>
<url-pattern> /servlet/Mo </url-pattern>
</servlet-mapping>
(c) Deploy the application
Using command line:
wdeploy deploy -u /foo
 -i yourserver
 -v https-yourserver
 -d c:\iplanet\examples\foo-dir
 Foo.war
(d) Change web-apps.xml file (for picking up ThirdParty.jar)
It is located in
C:\iPlanet\Servers\https-yourserver\config
You should see something similar to following after successful deployment.
<web-app uri="/foo" dir="C:\iPlanet\examples\foo-dir" enable="true"/>
Change it to look like following to pick up the ThirdParty.jar
<web-app uri="/foo" dir="C:\iPlanet\examples\foo-dir" enable="true">
<class-loader reload-interval="300"
 classpath="C:/iPlanet/examples/foo-dir/WEB-INF/lib/ThirdParty.jar"
 delegate="false"/>
</web-app>
(e) Change jvm12.conf file (for JNI)
It is located in
C:\iPlanet\Servers\https-yourserver\config
Add or uncomment the following lines:
#optional - just helps with instrumenting the jsp and servlet code
jvm.include.CLASSPATH=1
jvm.enableDebug=1
nes.jsp.enabledebug=1
jvm.trace=7
jvm.verboseMode=1
#required for JNI
java.compiler=NONE
jvm.classpath=.;C:\JDK1.3.1\lib\tools.jar;C:/iPlanet/Servers/plugins/servlets/examples/legacy/beans.10/SDKBeans10.jar;
jvm.option=-Xrs
jvm.option=-Xnoagent
# not sure if this is needed for iPlanet web server
jvm.option=-Djava.library.path=C:/iPlanet/examples/foo-dir/natlib/ -Djava.compiler=NONE
(f) Change magnus.conf file (for JNI)
We HAD to change this file in order for ThirdParty.jar file to pick up the native C++ code using JNI. Apparently, the
iPlanet Web Server doesn't pick the Environment Variable Path. Because when we had the directory containing the DLL just
in Path, it didn't work.
Change Extrapath directive:
ExtraPath C:/iPlanet/Servers/bin/https/bin;${NSES_JRE_RUNTIME_LIBPATH}
to
ExtraPath c:/iPlanet/examples/foo-dir/natlib;C:/iPlanet/Servers/bin/https/bin;${NSES_JRE_RUNTIME_LIBPATH}
(g) Apply changes from the Web Server Administration Console and Restart the web server.
You should be able to see the behaviour that you want from your application.
http://yourserver/foo/foo.jsp
Hope this was helpful!!!
Sonu

Deploying a WAR file containing .jsp and servlets (also uses JNI) on Windows 2000
We had problems making it initially work on Sun ONE Web Server 6.0 Service Pack 1 because of lack of good iPlanet Web
Server documentation on deploying such files.
This is how we went about it:
1) Make one of the servlet and JSP (must call another Java Class) web application (.war) examples work with iPlanet Web
Server.
C:\iPlanet\Servers\plugins\servlets\examples\web-apps\HelloWorld\HelloWorld.war
and
C:\iPlanet\Servers\plugins\servlets\examples\web-apps\jakarta-examples\jarkarta-examples.war
a) Go to your Web Server Administration to deploy the application using GUI Web Application Deploy.
(We usually use command line, we experienced some issues with the GUI version, but maybe it is fixed in the new Web Server
service packs)
From browser, open http://yourserver:8888/
Click on Select a Server:Manage
Click on Virtual Server Class
Click on https-yourserver
Click on the Web Applications Tab
Then, click on Deploy Web Application
Enter the following -
WAR File On: Local
WAR File Path: C:\iPlanet\Servers\plugins\servlets\examples\web-apps\jakarta-examples\jarkarta-examples.war
Application URI: /jakarta
Installation Directory: c:\iPlanet\examples\jakarta-examples
By clicking on OK it deployed the application.
I can verify that it is deployed by selecting "Edit Web Applications" and I see the following entry:
Edit /jakarta c:/iPlanet/examples/jakarta-examples
Also, c:/iPlanet/examples/jakarta-examples should have the similar following directory structure ..
- [images]
- [jsp]
- index.html
- [servlets]
- [META-INF]
- [WEB-INF]
- [classes]
- [tlds]
- web.xml
- index.html
I restarted the server and accessed it using the following URL from my IE browser:
http://yourserver/jakarta/index.html
Then I clicked on the JSP Examples and tried some JSP examples.
b) Alternatively, you can also deploy the same example from the command-line.
Make sure C:\iPlanet\Servers\bin\https\httpadmin\bin\ is in your path
wdeploy deploy -u /jakarta
 -i yourserver
 -v https-yourserver
 -d c:\iplanet\examples\jakarta-examples
 C:\iPlanet\Servers\plugins\servlets\examples\web-apps\jakarta-examples\jarkarta-examples.war
Restart the web server (I don't think you have to restart, but .. might as well).
2)Deploy your web-application
My Foo.war has the following structure.
You can use jar tf Foo.war to look at the file contents from command line (assuming you have JDK installed and the bin is
in your PATH)
Foo.war
- [META-INF]
- [WEB-INF]
- web.xml
- [classes]
- Bar.class
- MoServlet.class
- [lib]
- ThirdParty.jar
- [natlib]
- extlib.dll
- foo.jsp
Here is our application scenario:
foo.jsp uses a class call Bar (it is not in any package). The Bar java class uses classes from ThirdParty.jar. The
ThirdParty.jar in turn uses JNI to load library extlib.dll. foo.jsp also calls /servlet/Mo as well.
Now to deploy it, do the following:
(a) Make sure that within foo.jsp, you import the Bar class ( I don't know why you have to do it, but if you don't you get
JSP compile error).
<%@page language="java" import="Bar" contentType="text/html"%>
(b) Check web.xml (for Servlets)
Within web.xml, make sure you have the following mappings:
<servlet>
<servlet-name> MoLink </servlet-name>
<servlet-class> MoServlet </servlet-class>
</servlet>
<servlet-mapping>
<servlet-name> MoLink </servlet-name>
<url-pattern> /servlet/Mo </url-pattern>
</servlet-mapping>
(c) Deploy the application
Using command line:
wdeploy deploy -u /foo
 -i yourserver
 -v https-yourserver
 -d c:\iplanet\examples\foo-dir
 Foo.war
(d) Change web-apps.xml file (for picking up ThirdParty.jar)
It is located in
C:\iPlanet\Servers\https-yourserver\config
You should see something similar to following after successful deployment.
<web-app uri="/foo" dir="C:\iPlanet\examples\foo-dir" enable="true"/>
Change it to look like following to pick up the ThirdParty.jar
<web-app uri="/foo" dir="C:\iPlanet\examples\foo-dir" enable="true">
<class-loader reload-interval="300"
 classpath="C:/iPlanet/examples/foo-dir/WEB-INF/lib/ThirdParty.jar"
 delegate="false"/>
</web-app>
(e) Change jvm12.conf file (for JNI)
It is located in
C:\iPlanet\Servers\https-yourserver\config
Add or uncomment the following lines:
#optional - just helps with instrumenting the jsp and servlet code
jvm.include.CLASSPATH=1
jvm.enableDebug=1
nes.jsp.enabledebug=1
jvm.trace=7
jvm.verboseMode=1
#required for JNI
java.compiler=NONE
jvm.classpath=.;C:\JDK1.3.1\lib\tools.jar;C:/iPlanet/Servers/plugins/servlets/examples/legacy/beans.10/SDKBeans10.jar;
jvm.option=-Xrs
jvm.option=-Xnoagent
# not sure if this is needed for iPlanet web server
jvm.option=-Djava.library.path=C:/iPlanet/examples/foo-dir/natlib/ -Djava.compiler=NONE
(f) Change magnus.conf file (for JNI)
We HAD to change this file in order for ThirdParty.jar file to pick up the native C++ code using JNI. Apparently, the
iPlanet Web Server doesn't pick the Environment Variable Path. Because when we had the directory containing the DLL just
in Path, it didn't work.
Change Extrapath directive:
ExtraPath C:/iPlanet/Servers/bin/https/bin;${NSES_JRE_RUNTIME_LIBPATH}
to
ExtraPath c:/iPlanet/examples/foo-dir/natlib;C:/iPlanet/Servers/bin/https/bin;${NSES_JRE_RUNTIME_LIBPATH}
(g) Apply changes from the Web Server Administration Console and Restart the web server.
You should be able to see the behaviour that you want from your application.
http://yourserver/foo/foo.jsp
Hope this was helpful!!!
Sonu

Compilation error in creating shared library via JNI

Hi ALL,
I amin serious trouble with a problem. I am developing a Simulator, a function of which is to decode MPEG-2 Video files in real time and play it as well.I have got a MPEG-2 Decoder implemented in C from an open source and need to integrate with my Simulator which is writtebn in Java. The integration part I am doing via JNI(Java Native Interface). Now I have a bunch of C files in MPEG-2 decoder which are to be compiled during the Execution of the Java Simulator.Can anybody give some idea about how to call multiple C files from the Java Source through JNI at one go? Another problem I am facing is in calling a single C code from the traditional "HelloWorld" Java Code itself. The problem comes when I am trying to compile the shared library between the C native code and Java Code in my Linux Machine...I am getting the following message:
/usr/lib/gcc-lib/i386-redhat-linux/2.96/.../../../crt1.0 : In function '_start' :
/usr/lib/gcc-lib/i386-redhat-linux/2.96/.../../../crt1.0(.text+0x18): undefined reference to 'main'
collect2: ld retrurned 1 exit status
What does the above errot mean? How to rectify it.It will be of great help if you anybody can give me clues.

It means that your compiler options are wrong.
You need to create a shared library.
Instead you are creating an executable, which is not the same as a shared library.
If you search this forum you will find posts with command line options that work.

Problem calling C# dll using JNI

Hi,
I'm trying to call C# functions from a JNI interface. I built a C++ DLL to link the Java and C# calls together, but I am always getting the same error. Calling the C# DLL directly from the C++ code (compiled as an application) does not cause this error. I have to be able to connect our java application with a third party C# DLL, so I cannot just right the DLL directly in C++... Here is my code:
//C# Class Library::
namespace ClassLibrary2
 /// <summary>
 /// Summary description for Class1.
 /// </summary>
 public class Class1
 public Class1()
 // TODO: Add constructor logic here
 public void Bidon1()
 MessageBox.Show("Affiche", "Toi", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
//C++ DLL::
#using "ClassLibrary2.dll"
BOOL APIENTRY DLLMain(HANDLE hModule, DWORD ul_reason_for_call, LPVOID lpReserved) {
return TRUE;
JNIEXPORT void JNICALL Java_com_blablabla_CommJNIDLL_Init
(JNIEnv * enivronmt, jobject obj)
 new ClassLibrary2::Class1();
 (new ClassLibrary2::Class1())->Bidon1();
Olivier dit :
//Java JNI Calls::
//From CommJNIDLL::
 static {
 System.loadLibrary("MyCDLL");
 public native void Init(); If I comment the calls within the C++ DLL, they get fired, and no exception is raised. What am I doing wrong?
Thanks, bumpert

Hi,
I am currently also trying to call some C# code within JNI. So far I have managed to call some simple C# code in Java through JNI based on the example on codeproject. However, now my problem is that instead of doing JNI-->C++->M C++->C#, I need to include one more reference to some other DLLs in the C# code. Therefore I need to do JNI-->C++-->M C++-->C#-->DLL. So is there a way to do this? I can compile all the code sucessfully in C++, but when I try to execute the .netmodule (for C#) and DLL for C++ through JNI in Java, it gives me an error. I have tried to put all the relevant DLLs in the same directory, but it still does not work. So is there someway to combine the .netmodule of C# with the DLLs it references to? Perhaps that could solve the problem? I am new to C# and C++, really appreciate if someone can give some advices since there's nothing much on the net.
thanks,
Lee

Connection Pooling and JSP Custom Tag Library - is code (inside) the best way/correc?

Hi, can anyone advise as to whether my tag library code (based
on Apache Jakarta Project) will actually achieve connection
pooling functionality across my entire JSP based application? I
am slightly concerned that my OracleConnectionCacheImpl object
may exist multiple times, hence rendering my conection pooling
attempt useless.
package com.solved.tag.dbtags.connection;
import java.io.IOException;
import java.sql.Connection;
import java.sql.SQLException;
import javax.servlet.jsp.tagext.TagSupport;
import javax.servlet.jsp.JspTagException;
import javax.sql.DataSource;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import oracle.jdbc.pool.OracleConnectionCacheImpl;
* JSP tag connection, used to get a
* java.sql.Connection object.
* JSP Tag Lib Descriptor
* <pre>
* <name>connection</name>
<tagclass>com.solved.tag.dbtags.connection.ConnectionTag</t
agclass>
* <bodycontent>JSP</bodycontent>
<teiclass>com.solved.tag.dbtags.connection.ConnectionTEI</t
eiclass>
* <info>Opens a connection based on a jndiName.</info>
* <attribute>
* <name>id</name>
* <required>true</required>
* <rtexprvalue>false</rtexprvalue>
* </attribute>
* </pre>
* @author Matt Shannon
public class ConnectionTag extends TagSupport {
static private OracleConnectionCacheImpl cache = null;
public int doStartTag() throws JspTagException {
try {
Connection conn = null;
if (cache == null) {
try {
InitialContext ic = new InitialContext();
DataSource ds = (DataSource) ic.lookup
("jdbc/pool/OracleCache");
cache = (OracleConnectionCacheImpl)ds;
catch (NamingException ne) {
throw new JspTagException(ne.toString());
conn = cache.getConnection();
pageContext.setAttribute(getId(),conn);
catch (SQLException e) {
throw new JspTagException(e.toString());
return EVAL_BODY_INCLUDE;
package com.solved.tag.dbtags.connection;
import java.sql.Connection;
import java.sql.SQLException;
import javax.servlet.jsp.tagext.TagSupport;
* JSP tag closeconnection, used to close the
* specified java.sql.Connection.
* JSP Tag Lib Descriptor
* <pre>
* <name>closeConnection</name>
<tagclass>com.solved.tag.dbtags.connection.CloseConnectionTag&
lt;/tagclass>
* <bodycontent>empty</bodycontent>
* <info>Close the specified connection. The "conn"
attribute is the name of a
* connection object in the page context.</info>
* <attribute>
* <name>conn</name>
* <required>true</required>
* <rtexprvalue>false</rtexprvalue>
* </attribute>
* </pre>
* @author Matt Shannon
* @see ConnectionTag
public class CloseConnectionTag extends TagSupport {
private String _connId = null;
* The "conn" attribute is the name of a
* page context object containing a
* java.sql.Connection.
* @param connectionId
* attribute name of the java.sql.Connection to
close.
* @see ConnectionTag
public void setConn(String connectionId) {
_connId = connectionId;
public int doStartTag() {
try {
Connection conn = (Connection)pageContext.getAttribute
(_connId);
conn.close();
} catch (SQLException e) {
// failing to close a connection is not fatal
e.printStackTrace();
return EVAL_BODY_INCLUDE;
public void release() {
_connId = null;
package com.solved.tag.dbtags.connection;
import javax.servlet.jsp.tagext.TagData;
import javax.servlet.jsp.tagext.TagExtraInfo;
import javax.servlet.jsp.tagext.VariableInfo;
* TagExtraInfo for the connection tag. This
* TagExtraInfo specifies that the ConnectionTag
* assigns a java.sql.Connection object to the
* "id" attribute at the end tag.
* @author Matt Shannon
* @see ConnectionTag
public class ConnectionTEI extends TagExtraInfo {
public final VariableInfo[] getVariableInfo(TagData data)
return new VariableInfo[]
new VariableInfo(
data.getAttributeString("id"),
"java.sql.Connection",
true,
VariableInfo.AT_END
data-sources.xml:
<?xml version="1.0"?>
<!DOCTYPE data-sources PUBLIC "Orion data-
sources" "http://xmlns.oracle.com/ias/dtds/data-sources.dtd">
<data-sources>
<data-source
class="oracle.jdbc.pool.OracleConnectionCacheImpl"
name="jdbc/pool/OracleCache"
location="jdbc/pool/OracleCache"
url="jdbc:oracle:thin:@oracle1:1521:pdev"
>
<property name="maxLimit" value="15" />
<property name="cacheScheme" value="2" />
<property name="user" value="console" />
<property name="password" value="console" />
<description>
This DataSource is using an Oracle-native DataSource Class so as
to allow Oracle Specific extensions.
A getConnection() call on this DataSource will return
oracle.jdbc.driver.OracleConnection.
The connection returned is a logical connection.
The caching scheme in place is Fixed Wait. Refer below to
possible values.
Dynamic 1
Fixed Wait 2
Fixed Return Null 3
</description>
</data-source>
</data-sources>
many thanks,
Matt.

Hi. Show me your pool definition.
Joe
Ramamurthy wrote:
I am using the jsp custom tag library from BEA called sqltags.tld which came with Weblogic 5.1. Currently I am using Weblogic6.1 sp2 on Solaris.
I have created a Connection Pool for Sybase database using the driver com.sybase.jdbc.SybDriver.
When I created jsp page to connect to the connection pool using sqltags custom tag library, I am getting the error
"javax.servlet.jsp.JspException: Failed to write body content
at weblogic.taglib.sql.ConnectionTag.doAfterBody(ConnectionTag.java:43)
at jsp_servlet.__hubwcdata._jspService(__sampletest.java:1014)"
After this message, whenever I try to access the same jsp page I am getting the message
"javax.servlet.jsp.JspException: Failed to load JDBC driver: weblogic.jdbc.pool.D
river
at weblogic.taglib.sql.ConnectionTag.doStartTag(ConnectionTag.java:34)
at jsp_servlet.__hubwcdata._jspService(__sampletest.java:205)".
Can you please help me the reason why this problem is happening and how to fix this ?
This problem doexn't happen consistently. This occurs once in a while.
I tried to increase Login delay Seconds parameter in the Connection Pool to 15 sec. It didn't help me much.
Thanks for your help !!!
Ram

I have 2 photo albums on my iPhone that i want to delete. One is called "Photo Library" the other is called "iPhonePics". I cannot delete any of the photos in either album. How do I delete the photos and/or the albums?

I have 2 photo albums on my iPhone that i want to delete. One is called "Photo Library" the other is called "iPhonePics". I cannot delete any of the photos in either album. How do I delete the photos and/or the albums?

You can uncheck multiple songs by selecting all the songs you want to uncheck, then right-click and choose "uncheck selection". Also, make sure that you have checked "Sync only checked songs and videos" on the Summary tab of your iTunes sync settings or the sync process will ignore your selections.
You can remove all the photos from your camera roll using Preview on your Mac. Connect your phone to your Mac, open Preview, go to File>Import from iPhone. When your photos appear in Preview, select the photos you want to delete, then click on the icon at the bottom showing the red circle with the diagonal line through it (see image below), then click Delete.
To remove photos from the Photo Stream album on your phone you'll have to either reset Photo Stream (deleting all the photos from iCloud) or turn off Photo Stream on your phone.

Korean characters, not handled through JNI

Hello:
I have a C library that is wrapped through JNI. The data is in Korean, and is returning fine in the C code, but then when I access the data through Java (JString), it is all messed up. Any ideas what is the problem?
Thanks,
[email protected]

Adding on, here is the snippet code, where a command is passed in. The C code executes the command, and returns the result. The UTF and jstring string manipulations are shown below. What is wrong with the assumption if the data itself is of Korean language (double-byte enabled)? Any response would be greatly appreciated. Please respond to this message board, or email at [email protected]
Thanks,
Bilal
JNIEXPORT jshort JNICALL
Java_execCliCommand(
JNIEnv *env, jobject obj, jstring cliCmd, jobject cliOutObj)
jshort jresult;
P_HANDLE cliOut = (P_HANDLE)NULL;
char cliOutBuf = (char )NULL;
jclass jcliOutClass;
jfieldID joutbufID;
jstring jcliOutStr;
* Get the cli command & connectstring and execute the cli.
const char cliCmdStr = (env)->GetStringUTFChars(env, cliCmd, 0);
printf("CLI COMMAND : %s\n", (char *)cliCmdStr);
jresult = cliRunServerCommand((char *)cliCmdStr, &cliOut);
jcliOutClass = (*env)->GetObjectClass(env, cliOutObj);
joutbufID = (*env)->GetFieldID(env, jcliOutClass, "outbuf", "Ljava/lang/String;");
if ( cliOutBuf != NULL ) {
printf("CLI RESULTS: %s\n", cliOutBuf);
jcliOutStr = (*env)->NewString(env, (jchar *)cliOutBuf, (jsize)(p_strlen(cliOutBuf)+1));
printf("UNICODE CLI RESULTS: %s\n", (char *)(*env)->GetStringChars(env, jcliOutStr,0));
} else {
jcliOutStr = (*env)->NewStringUTF(env, "Command executed successfully");
(*env)->SetObjectField(env, cliOutObj, joutbufID, jcliOutStr);
(*env)->ReleaseStringUTFChars(env, cliCmd, cliCmdStr);
(*env)->ReleaseStringUTFChars(env, connectString, connectStr);
return jresult;
}

Passing Image data through JNI?

Hello,
I am trying find the fastest way to pass image data from Java through JNI. Passing Java images through JNI seems to be a very common thing to do so I expect there's an oft-used approach. Can anyone give me a good explanation of this or point me to some references?
I need to pass the image data to a C++ function which operates on this data, writing the results to a destination buffer which goes back to Java and gets put back into an image.
Currently, I'm using BufferedImages and getRGB to get an int array from my source image, passing this through JNI along with another int array to be used as the destination buffer, then calling setRGB with my destination buffer after the JNI function returns. getRGB() preserves the alpha channel of png files, which is functionality I need. The problem with this approach is that getRGB is extremely slow. It can take up to two seconds with a large image on my 1.2 Ghz Athlon. It seems to be performing a copy of the entire source image's data. Maybe there is a way to decode a jpg or png directly into an int array?
-Aaron Dwyer

Here's how you could do it for TYPE_4BYTE_ABGR
BufferedImage img=new BufferedImage(13,10,BufferedImage.TYPE_4BYTE_ABGR);
img.setRGB(0,0,0xff0000);
img.setRGB(5,1,0x00ff00);
img.setRGB(1,1,0xcafebabe);
DataBuffer db=img.getRaster().getDataBuffer();
int dataType=db.getDataType();
if (dataType!=DataBuffer.TYPE_BYTE)
     throw new IllegalStateException("I can do it only for TYPE_BYTE");
int imgType=img.getType();
if (imgType!=BufferedImage.TYPE_4BYTE_ABGR)
     throw new IllegalStateException("I can do it only for TYPE_4BYTE_ABGR");
DataBufferByte dbi=(DataBufferByte)db;
byte[] array=dbi.getData();
SampleModel model=img.getSampleModel();
if (!(model instanceof PixelInterleavedSampleModel))
     throw new IllegalStateException("I can do it only for PixelInterleavedSampleModel");
PixelInterleavedSampleModel pisModel=(PixelInterleavedSampleModel)model;
if (pisModel.getPixelStride()!=4)
     throw new IllegalStateException("I can do it only for pixel stride of 4");
if (dbi.getNumBanks()!=1)
     throw new IllegalStateException("I can do it only for 1 band");
int scanlineBytes=pisModel.getScanlineStride();
// Access the green Pixel on Position 5,1
System.out.println( (int)array[5*4 + scanlineBytes] &0xff);     // Alpha
System.out.println( (int)array[5*4+1 + scanlineBytes] &0xff);     // Red
System.out.println( (int)array[5*4+2 + scanlineBytes] &0xff);     // Green
System.out.println( (int)array[5*4+3 + scanlineBytes] &0xff);     // Blue     I've added some checks to make sure we're accessing the data the right way.

SetOut() through JNI ignored

I'm trying to redirect System.out/err through JNI within
a JNI application which allows running a java class as
a service. Essentially I have the following two classes:
class Service {
void init() { ...
void start() { ...
class LogUtil {
void setOut(String path) {
System.setOut(new PrintStream
(new FileOutputStream(path)));
Now from JNI, i invoke first LogUtil.setOut() to redirect
the stdout, then run the Service class itself. However,
even though the redirection seems to work fine, the
actual java stdout stream is not redirected. It is still
being written to the console. However, if I call the
method LogUtil.setOut() from within Service.init() (which
is also being invoked through JNI), then all works ok.
Any ideas how this could happen?
Help greatly appreciated,
roman

I have the same problem, I get Java level output redirected ok but the printf's from the native side are not.
What did you do differently?

JSP Call C Library through JNI ?

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