contentpane - Java getContentPane() NullPointerException on JFormatterTextField -

i trying create jformatted text field, when try add it, nullpointerexception gets thrown @ me. checked if stuff in correct order or if isn't null, doesn't seem so. might wrong though.

here block of code

public static void showtopic(string path) throws ioexception{     path = "topics/"+path+".txt";     system.out.println(path);     string[] topicfile = login.readfile(path);     int b =  login.readlines(path);      topic.main(null);     jformattedtextfield formattedtextfield = new jformattedtextfield();     formattedtextfield.seteditable(false);     formattedtextfield.setbounds(50, 50, 100, 100);       (int i=0;i<b;i++)         formattedtextfield.settext(topicfile[i]);      topic.contentframe.getcontentpane().add(formattedtextfield);   } 

and window frame

import java.awt.eventqueue;   public class topic {      static jframe contentframe;      /**      * launch application.      */     public static void main(string[] args) {         eventqueue.invokelater(new runnable() {             public void run() {                 try {                     topic window = new topic();                     window.contentframe.setvisible(true);                 } catch (exception e) {                     e.printstacktrace();                 }             }         });     }      /**      * create application.      */     public topic() {         initialize();     }      /**      * initialize contents of frame.      */     private void initialize() {         contentframe = new jframe();         contentframe.setbounds(100, 100, 550, 539);         contentframe.setdefaultcloseoperation(jframe.exit_on_close);         contentframe.getcontentpane().setlayout(null);          jbutton btnnewbutton = new jbutton("new button");         btnnewbutton.setbounds(435, 0, 89, 23);         contentframe.getcontentpane().add(btnnewbutton);      }  } 

thanks in advance :)