Here you can find the source of fromFile(File f)
public static String fromFile(File f) throws IOException
//package com.java2s; import java.io.File; import java.io.FileInputStream; import java.io.IOException; import java.io.InputStream; public class Main { public static String fromFile(File f) throws IOException { InputStream is = new FileInputStream(f); byte[] bs = new byte[is.available()]; is.read(bs);// w ww . j a v a 2 s .c o m is.close(); return new String(bs); } }