Java Utililty Methods File to String

File f = new File(strInput);
StringBuilder sb = new StringBuilder(new Long(f.length()).intValue());
FileInputStream fIn = new FileInputStream(strInput);
BufferedReader br = new BufferedReader(new InputStreamReader(fIn));
String line = null;
while ((line = br.readLine()) != null) {
    sb.append(line);
    sb.append("\n");
...

try (InputStream is = new BufferedInputStream(new FileInputStream(source));
        OutputStream os = new BufferedOutputStream(target)) {
    byte[] buffer = new byte[1024];
    int bytesRead = 0;
    while (bytesRead != -1) {
        bytesRead = is.read(buffer);
        if (bytesRead > 0) {
            os.write(buffer, 0, bytesRead);
...

try {
    return new BufferedInputStream(new FileInputStream(file));
} catch (final IOException ioEx) {
    throw new RuntimeException(ioEx);

FileInputStream fis = new FileInputStream(filename);
DataInputStream dis = new DataInputStream(fis);
byte[] bytes = new byte[dis.available()];
dis.readFully(bytes);
ByteArrayInputStream bais = new ByteArrayInputStream(bytes);
return bais;

return fileToString(f, Integer.MAX_VALUE);

if (f.exists()) {
    try {
        int bufsize = (int) f.length();
        InputStream fis = new FileInputStream(f);
        return streamToString(fis, bufsize);
    } catch (Exception e) {
        return null;
} else
    return null;

Scanner m = new Scanner(f);
String s = "";
while (m.hasNextLine()) {
    s = s + m.nextLine().trim() + "\n";
m.close();
return s.trim();

try {
    FileReader fr = new FileReader(f);
    char[] tmp = new char[(int) f.length()];
    char c;
    int j = 0;
    for (int i = fr.read(); i != -1; i = fr.read()) {
        c = (char) i;
        tmp[j] = c;
...

StringBuilder sb = new StringBuilder();
String line;
BufferedReader br = new BufferedReader(new FileReader(f));
while ((line = br.readLine()) != null) {
    sb.append(line);
return sb.toString();

try {
    StringBuffer buff = new StringBuffer();
    BufferedReader in = new BufferedReader(new FileReader(f));
    String line = null;
    while ((line = in.readLine()) != null) {
        buff.append(line);
        buff.append("\n");
    in.close();
    return new String[] { buff.toString() };
} catch (Exception e) {
    throw new RuntimeException(e);