Random.nextInt() causes java.lang.UnsatisfiedLinkError

[Rohan Redkar]

Hi,

I am completely stumped by this error that I getting.
I am using the Random class in the client package and not the native
Java Random.

import com.google.gwt.user.client.Random;

When I include this line in my code,

int index = Random.nextInt(1000);

I get the following exception in my log. Can anyone please point to my
fault? I tried to look through the archives but did not find anything
on this issue. Thanks.

[WARN] StandardContext[]Exception while dispatching incoming RPC call
com.google.gwt.user.server.rpc.UnexpectedException: Service method
'public abstract void edu.nyu.client.SuperplyService.onCreateGame
(java.lang.String,java.lang.String)' threw an unexpected exception:
java.lang.UnsatisfiedLinkError:
com.google.gwt.user.client.Random.nextInt(I)I
at com.google.gwt.user.server.rpc.RPC.encodeResponseForFailure
(RPC.java:360)
at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse
(RPC.java:546)
at com.google.gwt.user.server.rpc.RemoteServiceServlet.processCall
(RemoteServiceServlet.java:164)
at com.google.gwt.user.server.rpc.RemoteServiceServlet.doPost
(RemoteServiceServlet.java:86)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter
(ApplicationFilterChain.java:237)
at org.apache.catalina.core.ApplicationFilterChain.doFilter
(ApplicationFilterChain.java:157)
at org.apache.catalina.core.StandardWrapperValve.invoke
(StandardWrapperValve.java:214)
at org.apache.catalina.core.StandardValveContext.invokeNext
(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke
(StandardPipeline.java:520)
at org.apache.catalina.core.StandardContextValve.invokeInternal
(StandardContextValve.java:198)
at org.apache.catalina.core.StandardContextValve.invoke
(StandardContextValve.java:152)
at org.apache.catalina.core.StandardValveContext.invokeNext
(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke
(StandardPipeline.java:520)
at org.apache.catalina.core.StandardHostValve.invoke
(StandardHostValve.java:137)
at org.apache.catalina.core.StandardValveContext.invokeNext
(StandardValveContext.java:104)
at org.apache.catalina.valves.ErrorReportValve.invoke
(ErrorReportValve.java:118)
at org.apache.catalina.core.StandardValveContext.invokeNext
(StandardValveContext.java:102)
at org.apache.catalina.core.StandardPipeline.invoke
(StandardPipeline.java:520)
at org.apache.catalina.core.StandardEngineValve.invoke
(StandardEngineValve.java:109)
at org.apache.catalina.core.StandardValveContext.invokeNext
(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke
(StandardPipeline.java:520)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:
929)
at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:
160)
at org.apache.coyote.http11.Http11Processor.process
(Http11Processor.java:799)
at org.apache.coyote.http11.Http11Protocol
$Http11ConnectionHandler.processConnection(Http11Protocol.java:705)
at org.apache.tomcat.util.net.TcpWorkerThread.runIt
(PoolTcpEndpoint.java:577)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run
(ThreadPool.java:683)
at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.UnsatisfiedLinkError:
com.google.gwt.user.client.Random.nextInt(I)I
at com.google.gwt.user.client.Random.nextInt(Native Method)
at edu.nyu.client.model.gametype.Multiplication.setNextHint
(Multiplication.java:39)
at edu.nyu.client.model.Game.<init>(Game.java:44)
at edu.nyu.server.GameServiceImpl.onCreateGame(GameServiceImpl.java:
35)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse
(RPC.java:527)
at com.google.gwt.user.server.rpc.RemoteServiceServlet.processCall
(RemoteServiceServlet.java:164)
at com.google.gwt.user.server.rpc.RemoteServiceServlet.doPost
(RemoteServiceServlet.java:86)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter
(ApplicationFilterChain.java:237)
at org.apache.catalina.core.ApplicationFilterChain.doFilter
(ApplicationFilterChain.java:157)
at org.apache.catalina.core.StandardWrapperValve.invoke
(StandardWrapperValve.java:214)
at org.apache.catalina.core.StandardValveContext.invokeNext
(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke
(StandardPipeline.java:520)
at org.apache.catalina.core.StandardContextValve.invokeInternal
(StandardContextValve.java:198)
at org.apache.catalina.core.StandardContextValve.invoke
(StandardContextValve.java:152)
at org.apache.catalina.core.StandardValveContext.invokeNext
(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke
(StandardPipeline.java:520)
at org.apache.catalina.core.StandardHostValve.invoke
(StandardHostValve.java:137)
at org.apache.catalina.core.StandardValveContext.invokeNext
(StandardValveContext.java:104)
at org.apache.catalina.valves.ErrorReportValve.invoke
(ErrorReportValve.java:118)
at org.apache.catalina.core.StandardValveContext.invokeNext
(StandardValveContext.java:102)
at org.apache.catalina.core.StandardPipeline.invoke
(StandardPipeline.java:520)
at org.apache.catalina.core.StandardEngineValve.invoke
(StandardEngineValve.java:109)
at org.apache.catalina.core.StandardValveContext.invokeNext
(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke
(StandardPipeline.java:520)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:
929)
at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:
160)
at org.apache.coyote.http11.Http11Processor.process
(Http11Processor.java:799)
at org.apache.coyote.http11.Http11Protocol
$Http11ConnectionHandler.processConnection(Http11Protocol.java:705)
at org.apache.tomcat.util.net.TcpWorkerThread.runIt
(PoolTcpEndpoint.java:577)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run
(ThreadPool.java:683)
at java.lang.Thread.run(Unknown Source)

[Thomas Broyer]

Server-side you have to use Java's Random, not GWT's *client* Random
(which, obviously is for client-side code and defers to JavaScript on
way or another).

The exception you get is because GWT's Random.nextInt is a JSNI
method, i.e. a "native" Java method with some special comment in the
source so that the GWTCompiler knows how to transform it to
JavaScript. Because it is marked "native", a JVM tries to find its
implementation in native libraries, and in this case it doesn't find
any.