Oracle-JDBC dll file

[rajee bharara]

hi,
In our companey intranet , we have 6 java application running over same tomcat context. There is two EJB application whose EJB components r deployed on weblogic and web componets r in Tomcat and one application is using oracle thin driver and other 2 using sql server oci driver. B4 there is no problem.but we have created a new application using both sql server and oracle connection, as ocijdbc.dll file is already loaded in memory , its not creating or loading another dll file, i even tried to unregisted the driver but there is no sucess, is it possible to unload the dll file in memory or anything which would help???the exception cming is :

javax.servlet.ServletException: Native Library D:\oracle\ora90\BIN\ocijdbc9.dll already loaded in another classloader
org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:471)
org.apache.jsp.webPages.leaveManager_jsp._jspService(leaveManager_jsp.java:924)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:94)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:268)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:258)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:205)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)


root cause

java.lang.UnsatisfiedLinkError: Native Library D:\oracle\ora90\BIN\ocijdbc9.dll already loaded in another classloader
java.lang.ClassLoader.loadLibrary0(ClassLoader.java:1551)
java.lang.ClassLoader.loadLibrary(ClassLoader.java:1511)
java.lang.Runtime.loadLibrary0(Runtime.java:788)
java.lang.System.loadLibrary(System.java:834)
oracle.jdbc.oci8.OCIDBAccess.logon(OCIDBAccess.java:294)
oracle.jdbc.driver.OracleConnection.<init>(OracleConnection.java:307)
oracle.jdbc.driver.OracleDriver.getConnectionInstance(OracleDriver.java:442)
oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:321)
java.sql.DriverManager.getConnection(DriverManager.java:512)
java.sql.DriverManager.getConnection(DriverManager.java:171)
com.xavient.xavLeaveManager.DBConnection.getConn(DBConnection.java:167)
com.xavient.xavLeaveManager.LeaveManagerAction.getUserFullName(LeaveManagerAction.java:299)
org.apache.jsp.webPages.leaveManager_jsp._jspService(leaveManager_jsp.java:77)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:94)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:268)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:258)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:205)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)

please help me out as soon as possible. suggestion r welcome.

[Reid M. Pinchback]

It looks like you are using the OCI driver, which uses JNI.
You can't load a JNI resource multiple times in the same JVM.
You have three options:

1. Stop using the OCI driver, use the thin one instead.

2. Take the driver library out of your WEB-INF/lib directories
and move it into shared/lib instead.

3. (A refinement of 2) create a JMX component that will
manage the driver for Tomcat.

#3 is more hassle than you probably want, but it is why
Weblogic isn't complaining.

[Alex Deygan]

Follow this link to unload dll:

http://www.codethesis.com/blog/unload-java-jni-dll

I tried it with my web application running on Tomcat, and it works!

Briefly, I call System.loadLibrary from the class which is loaded by my custom class loader using reflection. This class is then removed by garbage collector.