java - I'm trying insert values into MySQL database, getting NullPointerException -

i'm trying insert data captured gui form database. when run program, , try add vendor, i'm getting nullpointerexception, , having trouble figuring out why. guidance appreciated.

java method:

private void addvendortodbbuttonactionperformed(java.awt.event.actionevent evt) {                                                               addvendorpanel.setvisible(true);           //andy:          string vendorname = addvendornamefield.gettext();          string customername = addcustomernumfield.gettext();          string vendorcode = addvendorcodefield1.gettext();       string sql = "insert vendors (vendor,cust#,vendorcode)"+"values('"+vendorname+"','"+customername+"','"+vendorcode+"')";      try {          openconnection();          rs = statement.executequery(sql);      } catch (sqlexception ex) {          logger.getlogger(gui.class.getname()).log(level.severe, null, ex);      } }        

openconnection:

public void openconnection(){      connection conn = null;         try {       conn = drivermanager.getconnection("jdbc:mysql://sql3.freemysqlhosting.net:3306/sql376856", "xxxx","xxxxx");       system.out.println("connected database successfully...");         } catch (exception e) {             system.out.println(e);         }     try {         statement statement = conn.createstatement();     } catch (sqlexception ex) {         logger.getlogger(gui.class.getname()).log(level.severe, null, ex);     } } 

declare global variables use:

public class gui extends javax.swing.jframe {    statement statement;    connection conn;  resultset rs; /**  * creates new form gui  */ public gui() {     initcomponents(); } 

error message:

run: connected database successfully... exception in thread "awt-eventqueue-0" java.lang.nullpointerexception @ database.gui.addvendortodbbuttonactionperformed(gui.java:1142) @ database.gui.access$1300(gui.java:23) @ database.gui$14.actionperformed(gui.java:562) @ javax.swing.abstractbutton.fireactionperformed(abstractbutton.java:2022) @        javax.swing.abstractbutton$handler.actionperformed(abstractbutton.java:2346) @ javax.swing.defaultbuttonmodel.fireactionperformed(defaultbuttonmodel.java:402) @ javax.swing.defaultbuttonmodel.setpressed(defaultbuttonmodel.java:259) @ javax.swing.plaf.basic.basicbuttonlistener.mousereleased(basicbuttonlistener.java:252) @ java.awt.component.processmouseevent(component.java:6527) @ javax.swing.jcomponent.processmouseevent(jcomponent.java:3321) @ java.awt.component.processevent(component.java:6292) @ java.awt.container.processevent(container.java:2234) @ java.awt.component.dispatcheventimpl(component.java:4883) @ java.awt.container.dispatcheventimpl(container.java:2292) @ java.awt.component.dispatchevent(component.java:4705) @ java.awt.lightweightdispatcher.retargetmouseevent(container.java:4898) @ java.awt.lightweightdispatcher.processmouseevent(container.java:4533) @ java.awt.lightweightdispatcher.dispatchevent(container.java:4462) @ java.awt.container.dispatcheventimpl(container.java:2278) @ java.awt.window.dispatcheventimpl(window.java:2739) @ java.awt.component.dispatchevent(component.java:4705) @ java.awt.eventqueue.dispatcheventimpl(eventqueue.java:746) @ java.awt.eventqueue.access$400(eventqueue.java:97) @ java.awt.eventqueue$3.run(eventqueue.java:697) @ java.awt.eventqueue$3.run(eventqueue.java:691) @ java.security.accesscontroller.doprivileged(native method) @ java.security.protectiondomain$1.dointersectionprivilege(protectiondomain.java:75) @ java.security.protectiondomain$1.dointersectionprivilege(protectiondomain.java:86) @ java.awt.eventqueue$4.run(eventqueue.java:719) @ java.awt.eventqueue$4.run(eventqueue.java:717) @ java.security.accesscontroller.doprivileged(native method) @ java.security.protectiondomain$1.dointersectionprivilege(protectiondomain.java:75) @ java.awt.eventqueue.dispatchevent(eventqueue.java:716) @ java.awt.eventdispatchthread.pumponeeventforfilters(eventdispatchthread.java:201) @ java.awt.eventdispatchthread.pumpeventsforfilter(eventdispatchthread.java:116) @ java.awt.eventdispatchthread.pumpeventsforhierarchy(eventdispatchthread.java:105) @ java.awt.eventdispatchthread.pumpevents(eventdispatchthread.java:101) @ java.awt.eventdispatchthread.pumpevents(eventdispatchthread.java:93) @ java.awt.eventdispatchthread.run(eventdispatchthread.java:82) 

i think statement variable in method addvendortodbbuttonactionperformed null , hence nullpointer exception.