一个Struts的错误，帮忙看看

hevil 2004-03-28 05:48:23

[WARN] RequestProcessor - -Unhandled Exception thrown: class java.lang.NullPoint
erException
<2004/3/28 下午05時43分26秒> <Error> <HTTP> <101017> <[ServletContext(id=456470,
name=demo,context-path=/demo)] Root cause of ServletException
java.lang.NullPointerException
at com.fly.struts.form.RegistAction.execute(RegistAction.java:48)
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.doPost(ActionServlet.java:525)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:760)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at weblogic.servlet.internal.ServletStubImpl$ServletInvocationAction.run
(ServletStubImpl.java:1058)
at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubIm
pl.java:401)
at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubIm
pl.java:306)
at weblogic.servlet.internal.WebAppServletContext$ServletInvocationActio
n.run(WebAppServletContext.java:5445)
at weblogic.security.service.SecurityServiceManager.runAs(SecurityServic
eManager.java:780)
at weblogic.servlet.internal.WebAppServletContext.invokeServlet(WebAppSe
rvletContext.java:3105)
at weblogic.servlet.internal.ServletRequestImpl.execute(ServletRequestIm
pl.java:2588)
at weblogic.kernel.ExecuteThread.execute(ExecuteThread.java:213)
at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:189)
>

这是什么原因啊？

...全文