java - Trying to use Button to insert TextField into database -

i trying use button insert multiple textfield's database. able insert raw strings database via: have made few changes after suggestions.

public class dataentry extends mysqlclass {     static label jnaam = new label("naam");   static textfield lnaam = new textfield(30);     static  label jemail =new label("e-mail"); static textfield lemail=new textfield(30);     static  label jadres =new label("adres");  static textfield ladres =new textfield(30);     static  label jplaats =new label("plaats"); static textfield lplaats =new textfield(100);     static  label jpostcode =new label("postcode"); static textfield lpostcode =new textfield(6);     static  label jtelefoon =new label("telefoon");static textfield ltelefoon =new textfield(13);     static  label jbedrijfsnaam =new label("bedrijfsnaam"); static textfield     lbedrijfsnaam =new textfield(30);       public static void main(string[] args) throws exception {   frame frm=new frame("dataentry frame");   label lbl = new label("please fill blank:");   frm.add(lbl);   frm.setsize(850, 500);   frm.setvisible(true);   frm.addwindowlistener(new windowadapter(){    public void windowclosing(windowevent e){   system.exit(0);   }   });   panel p = new panel();   panel p1 = new panel();    p.setlayout(new gridlayout(100,1));   p.add(jnaam);         p.add(lnaam);   p.add(jemail);        p.add(lemail);   p.add(jadres);        p.add(ladres);   p.add(jplaats);       p.add(lplaats);   p.add(jpostcode);     p.add(lpostcode);   p.add(jtelefoon);     p.add(ltelefoon);   p.add(jbedrijfsnaam); p.add(lbedrijfsnaam);  // button submit=new button("save");       //p.add(submit);    p1.add(p);   frm.add(p1,borderlayout.north);    button submit = new button("save");   p.add(submit);   submit.addactionlistener(new actionlistener() {        @override       public void actionperformed(actionevent e) {           pushdata();        }   }); }  public static void pushdata() {   try {       preparedstatement.setstring(1, lnaam.gettext());       preparedstatement.setstring(2, lemail.gettext());       preparedstatement.setstring(3, ladres.gettext());       preparedstatement.setstring(4, lplaats.gettext());       preparedstatement.setstring(5, lpostcode.gettext());       preparedstatement.setstring(6, ltelefoon.gettext());       preparedstatement.setstring(7, lbedrijfsnaam.gettext());       preparedstatement.executeupdate();   } catch (sqlexception e) {       e.printstacktrace();   }  } }    

http://i.imgur.com/u380tp3.jpg

this new error receiving:

exception in thread "awt-eventqueue-0" java.lang.nullpointerexception @ dataentry.pushdata(dataentry.java:66) @ dataentry$2.actionperformed(dataentry.java:58) @ java.awt.button.processactionevent(unknown source) @ java.awt.button.processevent(unknown source) @ java.awt.component.dispatcheventimpl(unknown source) @ java.awt.component.dispatchevent(unknown source) @ java.awt.eventqueue.dispatcheventimpl(unknown source) @ java.awt.eventqueue.access$200(unknown source) @ java.awt.eventqueue$3.run(unknown source) @ java.awt.eventqueue$3.run(unknown source) @ java.security.accesscontroller.doprivileged(native method) @ java.security.protectiondomain$1.dointersectionprivilege(unknown source) @ java.security.protectiondomain$1.dointersectionprivilege(unknown source) @ java.awt.eventqueue$4.run(unknown source) @ java.awt.eventqueue$4.run(unknown source) @ java.security.accesscontroller.doprivileged(native method) @ java.security.protectiondomain$1.dointersectionprivilege(unknown source) @ java.awt.eventqueue.dispatchevent(unknown source) @ java.awt.eventdispatchthread.pumponeeventforfilters(unknown source) @ java.awt.eventdispatchthread.pumpeventsforfilter(unknown source) @ java.awt.eventdispatchthread.pumpeventsforhierarchy(unknown source) @ java.awt.eventdispatchthread.pumpevents(unknown source) @ java.awt.eventdispatchthread.pumpevents(unknown source) @ java.awt.eventdispatchthread.run(unknown source) 

i've began write, i'll post (i'm not creating gui here, labels , textfields)

class stackoverflow {     preparedstatement preparedstatement;     label jnaam;     textfield lnaam;     label jemail;     textfield lemail;     label jadres;     textfield ladres;     label jplaats;     textfield lplaats;     label jpostcode;     textfield lpostcode;     label jtelefoon;     textfield ltelefoon;     label jbedrijfsnaam;     textfield lbedrijfsnaam;  public stackoverflow() {     initgui(); }  private void initgui() {     jnaam = new label("naam");     lnaam = new textfield(30);     jemail = new label("e-mail");     lemail = new textfield(30);     jadres = new label("adres");     ladres = new textfield(30);     jplaats = new label("plaats");     lplaats = new textfield(100);     jpostcode = new label("postcode");     lpostcode = new textfield(6);     jtelefoon = new label("telefoon");     ltelefoon = new textfield(13);     jbedrijfsnaam = new label("bedrijfsnaam");     lbedrijfsnaam = new textfield(30);      jbutton save = new jbutton("save");     save.addactionlistener(new actionlistener() {          @override         public void actionperformed(actionevent e) {             pushdata();          }     }); }  private void pushdata() {     try {         preparedstatement.setstring(1, lnaam.gettext());         preparedstatement.setstring(2, lemail.gettext());         preparedstatement.setstring(3, ladres.gettext());         preparedstatement.setstring(4, lplaats.gettext());         preparedstatement.setstring(5, lpostcode.gettext());         preparedstatement.setstring(6, ltelefoon.gettext());         preparedstatement.setstring(7, lbedrijfsnaam.gettext());         preparedstatement.executeupdate();     } catch (sqlexception e) {         e.printstacktrace();     }  } 

}