ServerAction extends AbstractAction { public void addHeader(String name, String value) { Map<String, String> map = getHeaders(); if (map == null) { map = new HashMap<String, String>(); setHeaders(map); } map.put(name, value); } ServerAction();  ServerAction(String name);  ServerAction(String name, String command);  ServerAction(String name, Icon icon);  ServerAction(String name, String command, Icon icon); void setURL(String url); String getURL(); void addParam(String name, String value); String getParamValue(String name); Set<String> getParamNames(); void addHeader(String name, String value); String getHeaderValue(String name); Set<String> getHeaderNames(); @Override void actionPerformed(ActionEvent evt);  }
@Test public void testNPEAddHeader() { ServerAction action = new ServerAction(); action.addHeader("key", "value"); }