java.lang.NullPointerException

[leonardo ginting]

hi guys how do i could fix this error

java.lang.NullPointerException


thanks in advance

[Bajrang Asthana]

When you try to access any property of an object that is null or have no instance attached with it.

for example:

Class Test{
int x;
public int getX(){
return x;
}
public void static main(String args[]){

Test test =null;
test.getX(); // Here you get java.lang.NullPointerException

}

}

to deal with this exception, you should first check the reference of object for null then access any method or property of associated to an object.

something similar-

if(null != test){
test.getX();
}

[H Jetly]

I think you should post such questions in Java In General Forum

[leonardo ginting]

hi guys thanks for reply this is about jsf and richfaces so i post in this section
b.t.w this is my code please corect me
ok first this is error i' got
when i tried to click edit button so when popup panel is appear then i change the value in the field then i click save button then this error come out

type Exception report

message

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

exception

javax.servlet.ServletException
	javax.faces.webapp.FacesServlet.service(FacesServlet.java:277)
	org.ajax4jsf.webapp.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:206)
	org.ajax4jsf.webapp.BaseFilter.handleRequest(BaseFilter.java:295)
	org.ajax4jsf.webapp.BaseFilter.processUploadsAndHandleRequest(BaseFilter.java:393)
	org.ajax4jsf.webapp.BaseFilter.doFilter(BaseFilter.java:520)
	org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)

root cause

java.lang.NullPointerException
	id.co.compnet.visa.web.converter.KelompokBiayaConverter.getAsObject(KelompokBiayaConverter.java:30)

this is my code KelompokBiayaConverter.java

public class KelompokBiayaConverter implements Converter {

    /** Creates a new instance of MasterBiayaConverter */
 

    public Object getAsObject(FacesContext fc, UIComponent uic, String string) {
//        throw new UnsupportedOperationException("Not supported yet."); 
        if (string == null || string.length() == 0){
            
            return null;        
            }
        Long id = new Long (string);
        MasterBiayaMBean controller = (MasterBiayaMBean)fc.getApplication().getELResolver().getValue(fc.getELContext(), null , "MasterBiayaMbean");
                return controller.getKelompokBiayaJpaController().findKelompokBiaya(id);
    }

    public String getAsString(FacesContext fc, UIComponent uic, Object o) {
//        throw new UnsupportedOperationException("Not supported yet.");
        if (o == null)
            return null;
        if (o instanceof KelompokBiaya){
        KelompokBiaya kelompokBiaya = (KelompokBiaya) o;
        return kelompokBiaya.getKelompokbiayaid() == null ? "" : kelompokBiaya.getKelompokbiayaid().toString();
                 
        }else{ throw new IllegalArgumentException("object"+o+ "is of type"+o.getClass().getName()+"; expected type : id.co.compnet.api.keu.jpa.KelompokBiaya" );}
    }
    
    
}

help me out please,...
if you think that im wrong please tell me what should i change or add the code

thanks guys

[Tim Holloway]

So which line in your sample code is "line 30"?

[leonardo ginting]

Tim Holloway wrote:So which line in your sample code is "line 30"?

hi tim thanks for reply in those line,,
line 30 is at line 14

[Ilari Moilanen]

Check whether controller is null or whether getKelompokBiayaJpaController() method returns null. Based on your error message (I presume that you showed the root cause correctly) the controller object is null. So you have to find out why either MasterBiyanMbean is not present or why fetching the object does not work. Very basic stuff (null checks and all).