Native library cannot be loaded twice

[Andreas Hirner <an...@projektinter.net>]

Hello,

I have a problem calling a native library within a servlet. The
library is initialised like that:

static {
  try {
   System.loadLibrary("mapscript");
   System.err.println("libmapscript.so loaded");
   }
  catch (UnsatisfiedLinkError e) {
   System.err.println("libmapscript.so not loaded: " + e);
   }
 }

Everything works fine. However, if I make changes to the servlet and
reload it via the

http://localhost:8080/manager/reload?path=/application

call, and ececute the servlet doing

http://localhost:8080/application/servlet/servletname

I get the following error message listed below. I have to restart
Tomcat in order to check any changes made to the servlet. Does anybody
know how to solve this problem?

Thank you in advance
Andy


################################################
Error Message
################################################
exception
javax.servlet.ServletException: Servlet execution threw an exception
at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Appli
cationFilterChain.java:269)
at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFi
lterChain.java:193)
at
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperVa
lve.java:243)
at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.
java:566)
at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java
:472)
at
org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)
at
org.apache.catalina.core.StandardContextValve.invoke(StandardContextVa
lve.java:201)
at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.
java:566)
at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java
:472)
at
org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)
at
org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2
344)
at
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.ja
va:164)
at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.
java:566)
at
org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcher
Valve.java:170)
at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.
java:564)
at
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.ja
va:170)
at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.
java:564)
at
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:4
62)
at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.
java:564)
at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java
:472)
at
org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)
at
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValv
e.java:163)
at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.
java:566)
at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java
:472)
at
org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)
at
org.apache.catalina.connector.http.HttpProcessor.process(HttpProcessor
.java:1011)
at
org.apache.catalina.connector.http.HttpProcessor.run(HttpProcessor.jav
a:1106)
at java.lang.Thread.run(Thread.java:484)


root cause

java.lang.UnsatisfiedLinkError: get_FTString
at edu.umn.gis.mapscript.mapscript.get_FTString(Native Method)
at edu.umn.gis.mapscript.mapscript.(mapscript.java:767)
at edu.umn.gis.mapscript.mapObj.(mapObj.java:227)
at demo.doGet(demo.java:75)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:740)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Appli
cationFilterChain.java:247)
at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFi
lterChain.java:193)
at
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperVa
lve.java:243)
at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.
java:566)
at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java
:472)
at
org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)
at
org.apache.catalina.core.StandardContextValve.invoke(StandardContextVa
lve.java:201)
at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.
java:566)
at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java
:472)
at
org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)
at
org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2
344)
at
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.ja
va:164)
at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.
java:566)
at
org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcher
Valve.java:170)
at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.
java:564)
at
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.ja
va:170)
at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.
java:564)
at
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:4
62)
at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.
java:564)
at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java
:472)
at
org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)
at
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValv
e.java:163)
at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.
java:566)
at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java
:472)
at
org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)
at
org.apache.catalina.connector.http.HttpProcessor.process(HttpProcessor
.java:1011)
at
org.apache.catalina.connector.http.HttpProcessor.run(HttpProcessor.jav
a:1106)
at java.lang.Thread.run(Thread.java:484)







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