Java: Read File Into String

method_1.java

String readFile(String fileName) throws IOException {
    BufferedReader br = new BufferedReader(new FileReader(fileName));
    try {
        StringBuilder sb = new StringBuilder();
        String line = br.readLine();

        while (line != null) {
            sb.append(line);
            sb.append("\n");
            line = br.readLine();
        }
        return sb.toString();
    } finally {
        br.close();
    }
}

method_2.java

try(BufferedReader br = new BufferedReader(new FileReader("file.txt"))) {
        StringBuilder sb = new StringBuilder();
        String line = br.readLine();

        while (line != null) {
            sb.append(line);
            sb.append(System.lineSeparator());
            line = br.readLine();
        }
        String everything = sb.toString();
    }

method_3.java

    FileInputStream inputStream = new FileInputStream("foo.txt");
    try {
        String everything = IOUtils.toString(inputStream);
    } finally {
        inputStream.close();
    }

method_4.java

 try(FileInputStream inputStream = new FileInputStream("foo.txt")) {
        Session IOUtils;
        String everything = IOUtils.toString(inputStream);
    }