Reading a file into string in Java

I am quite new to Java, and I am trying to read a file into a string (or should I use byte arrays for this?). File can be anything, such as a text file or executable file etc. I will compress what I read and write it to another file.

I am thinking of using this code:

public static String readFile(File f) {
    StringBuilder sb = new StringBuilder();
    try (BufferedReader br = new BufferedReader(new FileReader(f))) {
        String sCurrentLine;
        while ((sCurrentLine = br.readLine()) != null) {
            sb.append(sCurrentLine);
        }

    } catch (IOException e) {
        System.err.println("I/O Exception:" + e.getMessage());
        return null;
    }
    return sb.toString();
}

Does this look good to you? I was reading "Reading and writing text files" and I was a little bit confused over all the different ways one can use to read files.

Why reinvent the wheel?

Use commons-io's FileUtils.readFileToByteArray(File)(javadoc)

StackExchange Code Review Q#29521, answer score: 2