Null pointer exception when there is no value for numeric field in JSP

Question

I am using bean to validate the form of JSP. If use setProperty and if some fields on the form is left blank it is throwing a null pointer exception. This exception is happening only if the field is happen to be numbers in the bean. I cant do validation without calling setProperty of bean. Is there any other way to do this ? The code i am using is as follows.

<jsp:useBean id="addBean" scope="request" class="org.mypackage.products.add_product6_Variables" />
    <jsp:setProperty name="addBean" property="*" />

My Error:

org.apache.jasper.JasperException: An exception occurred processing JSP page /response.jsp at line 19

19: jsp:setProperty name="addBean" property="*" />

type Exception report

message 

description The server encountered an internal error () that prevented it from fulfilling this request.

exception 

org.apache.jasper.JasperException: org.apache.jasper.JasperException: org.apache.jasper.JasperException: error in invoking method
    org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:500)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:410)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:717)


root cause 

org.apache.jasper.JasperException: org.apache.jasper.JasperException: error in invoking method
    org.apache.jasper.runtime.JspRuntimeLibrary.internalIntrospecthelper(JspRuntimeLibrary.java:361)
    org.apache.jasper.runtime.JspRuntimeLibrary.introspecthelper(JspRuntimeLibrary.java:308)
    org.apache.jasper.runtime.JspRuntimeLibrary.introspect(JspRuntimeLibrary.java:286)
    org.apache.jsp.response_jsp._jspService(response_jsp.java:77)
    org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:386)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:717)


root cause 

org.apache.jasper.JasperException: error in invoking method
    org.apache.jasper.runtime.JspRuntimeLibrary.createTypedArray(JspRuntimeLibrary.java:533)
    org.apache.jasper.runtime.JspRuntimeLibrary.internalIntrospecthelper(JspRuntimeLibrary.java:350)
    org.apache.jasper.runtime.JspRuntimeLibrary.introspecthelper(JspRuntimeLibrary.java:308)
    org.apache.jasper.runtime.JspRuntimeLibrary.introspect(JspRuntimeLibrary.java:286)
    org.apache.jsp.response_jsp._jspService(response_jsp.java:77)
    org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:386)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:717)


root cause 

java.lang.NumberFormatException: empty String
    sun.misc.FloatingDecimal.readJavaFormatString(FloatingDecimal.java:994)
    java.lang.Float.valueOf(Float.java:388)
    org.apache.jasper.runtime.JspRuntimeLibrary.createTypedArray(JspRuntimeLibrary.java:516)
    org.apache.jasper.runtime.JspRuntimeLibrary.internalIntrospecthelper(JspRuntimeLibrary.java:350)
    org.apache.jasper.runtime.JspRuntimeLibrary.introspecthelper(JspRuntimeLibrary.java:308)
    org.apache.jasper.runtime.JspRuntimeLibrary.introspect(JspRuntimeLibrary.java:286)
    org.apache.jsp.response_jsp._jspService(response_jsp.java:77)
    org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:386)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

Basanth Roy Basanth Roy · Accepted Answer · 2011-07-10T15:06:47

Is your bean property type a primitive number or the wrapped object type? I mean int or Integer?

It probably is of type int now since int and other primitives cannot be set to null; while an Integer object can be set to null.

Can you change your bean property type to Integer etc and check whether the NPE still exists?

Null pointer exception when there is no value for numeric field in JSP

1 Answers