Java - Retrieve image on the server side -

i trying retrieve image display in pdf (this on server side). however, no mater path try null pointer exception. code is:

try {         //option 1         classloader classloader = thread.currentthread().getcontextclassloader();         system.out.println("image path 1");         string path = classloader.getresource("image/1ster_icon_256.png").getpath();         //string path = classloader.getresource("/image/1ster_icon_256.png").getpath();         //string path = classloader.getresource("war/image/1ster_icon_256.png").getpath();         //string path = classloader.getresource("/war/image/1ster_icon_256.png").getpath();         system.out.println("image path = " + path);         image image1 = image.getinstance(path);          preface.add(image1);         document.add(preface);     } catch(exception e){       e.printstacktrace();     }   } 

and error is:

image path 1 java.lang.nullpointerexception 

i have tried other examples search; however, have code exceptions.