Header header2 = new BasicHeader("name2", "value2");
Header header3 = new BasicHeader("name3", "value3");
headergroup.addHeader(header1);
headergroup.addHeader(header2);
headergroup.addHeader(header3);
headergroup.updateHeader(new BasicHeader("name2", "newvalue"));
headergroup.updateHeader(new BasicHeader("name4", "value4"));
headergroup.updateHeader(null);
assertEquals(4, headergroup.getAllHeaders().length);
assertEquals("newvalue", headergroup.getFirstHeader("name2").getValue());
}