java.lang.IllegalArgumentException: object is not an instance of declaring class,Stu

java.lang.IllegalArgumentException: object is not an instance of declaring class
 
  at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.
  java:39)
  at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAcces
  sorImpl.java:25)
  at java.lang.reflect.Method.invoke(Method.java:324)
  at org.apache.commons.beanutils.PropertyUtils.getSimpleProperty(Property
  Utils.java:1185)
  at org.apache.commons.beanutils.BeanUtils.copyProperties(BeanUtils.java:
  262)
  at net.stone.it.delphi.control.ToViewListBean.componentToVoList(ToViewLi
  stBean.java:41)
  at net.stone.it.delphi.control.ToViewListBean.toVoList(ToViewListBean.ja
  va:15)
  at net.stone.it.delphi.control.ComponentAction.execute(ComponentAction.j
  ava:40)
  at org.apache.struts.action.RequestProcessor.processActionPerform(Reques
  tProcessor.java:484)
  at org.apache.struts.action.RequestProcessor.process(RequestProcessor.ja
  va:274)
  at org.apache.struts.action.ActionServlet.process(ActionServlet.java:148
  2)
  at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:507)
  at javax.servlet.http.HttpServlet.service(HttpServlet.java:740)
  at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
  at weblogic.servlet.internal.ServletStubImpl$ServletInvocationAction.run
  (ServletStubImpl.java:971)
  at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubIm
  pl.java:402)
  at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubIm
  pl.java:305)
  at weblogic.servlet.internal.WebAppServletContext$ServletInvocationActio
  n.run(WebAppServletContext.java:6350)
  at weblogic.security.acl.internal.AuthenticatedSubject.doAs(Authenticate
  dSubject.java:317)
  at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:
  118)
  at weblogic.servlet.internal.WebAppServletContext.invokeServlet(WebAppSe
  rvletContext.java:3635)
  at weblogic.servlet.internal.ServletRequestImpl.execute(ServletRequestIm
  pl.java:2585)
  at weblogic.kernel.ExecuteThread.execute(ExecuteThread.java:197)
  at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:170)