Java Utililty Methods File Content Read

String ret = null;
InputStreamReader input = null;
StringWriter output = null;
try {
    input = new InputStreamReader(new FileInputStream(f), "UTF-8");
    output = new StringWriter();
    char[] buf = new char[1024];
    int n = 0;
...

return getFileContent(f.getCanonicalPath());

byte[] b = new byte[28];
InputStream inputStream = null;
try {
    inputStream = new FileInputStream(file);
    inputStream.read(b, 0, 28);
} catch (IOException e) {
    e.printStackTrace();
    throw e;
...

StringBuilder sb = new StringBuilder();
String lineSep = "\n";
try (BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(file), "UTF-8"))) {
    String line = br.readLine();
    while (line != null) {
        sb.append(line);
        sb.append(lineSep);
        line = br.readLine();
...

BufferedReader in = null;
StringBuffer szBuf;
String line;
try {
    in = new BufferedReader(new FileReader(file));
    szBuf = new StringBuffer();
    while ((line = in.readLine()) != null) {
        szBuf.append(line);
...

Long fileLengthLong = file.length();
byte[] fileContent = new byte[fileLengthLong.intValue()];
FileInputStream inputStream = new FileInputStream(file);
inputStream.read(fileContent);
inputStream.close();
String string = new String(fileContent);
return string;

byte[] bytes = new byte[(int) file.length()];
DataInputStream stream = null;
try {
    stream = new DataInputStream(new FileInputStream(file));
    stream.readFully(bytes);
    return bytes;
} catch (IOException e) {
    throw new RuntimeException(e);
...

StringWriter stringWriter = new StringWriter();
PrintWriter printWriter = new PrintWriter(stringWriter);
try (BufferedReader reader = new BufferedReader(new FileReader(file))) {
    String line;
    while ((line = reader.readLine()) != null) {
        printWriter.print(line + System.lineSeparator());
return stringWriter.toString();

StringBuilder contents = new StringBuilder();
try {
    BufferedReader input = new BufferedReader(new FileReader(file));
    try {
        String line = null; 
        while ((line = input.readLine()) != null) {
            contents.append(line);
            contents.append(System.getProperty("line.separator"));
...

FileInputStream f = null;
try {
    byte[] buffer = new byte[(int) file.length()];
    f = new FileInputStream(file);
    f.read(buffer);
    return new String(buffer);
} catch (IOException e) {
    throw new RuntimeException(e);
...