Java Utililty Methods HTTP Response

long modified;
if (connection instanceof JarURLConnection) {
    URL jarFileUrl = ((JarURLConnection) connection).getJarFileURL();
    URLConnection jarFileConnection = jarFileUrl.openConnection();
    try {
        modified = jarFileConnection.getLastModified();
    } finally {
        try {
...

long lastModified = 0L;
try {
    if (url.getProtocol().equals(JAR_PROTOCOL)) {
        JarURLConnection jarConn = (JarURLConnection) url.openConnection();
        url = jarConn.getJarFileURL();
    if (url.getProtocol().equals(FILE_PROTOCOL)) {
        File file;
...

String s = getResponseContent(httpConn);
responseContent.setLength(0);
responseContent.append(s);
s = getResponseHeaders(httpConn, headers);
responseCode.setLength(0);
responseCode.append(s);
return;

URLConnection yc = request.openConnection();
BufferedReader in = new BufferedReader(new InputStreamReader(yc.getInputStream()));
StringBuilder sb = new StringBuilder();
String inputLine;
while ((inputLine = in.readLine()) != null) {
    sb.append(inputLine);
in.close();
...

StringBuffer response = new StringBuffer();
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod(GET);
try (BufferedReader br = new BufferedReader(new InputStreamReader(connection.getInputStream()))) {
    String sCurrentLine;
    while ((sCurrentLine = br.readLine()) != null) {
        response.append(sCurrentLine);
return response.toString();

String charset = getResponseCharset(conn.getContentType());
InputStream es = conn.getErrorStream();
if (es == null) {
    return getStreamAsString(conn.getInputStream(), charset);
} else {
    String msg = getStreamAsString(es, charset);
    if (isEmpty(msg)) {
        throw new IOException(conn.getResponseCode() + ":" + conn.getResponseMessage());
...

BufferedReader br = null;
StringBuilder body = null;
String line = "";
try {
    br = new BufferedReader(new InputStreamReader(conn.getInputStream()));
    body = new StringBuilder();
    while ((line = br.readLine()) != null)
        body.append(line);
...

InputStream is = connection.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
String line;
StringBuffer response = new StringBuffer();
try {
    while ((line = reader.readLine()) != null) {
        response.append(line);
        response.append('\n');
...

try {
    if (httpConn.getInputStream() == null) {
        return null;
    } else {
        StringBuilder sb = new StringBuilder();
        BufferedReader in = new BufferedReader(new InputStreamReader(httpConn.getInputStream()));
        String str;
        while ((str = in.readLine()) != null) {
...

StringBuffer responseString = new StringBuffer();
URLConnection connection = new URL(url).openConnection();
BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
String aux;
while ((aux = in.readLine()) != null) {
    responseString.append(aux);
in.close();
...