FileReader and BufferedReader

FileReader is used for input of character data from a disk file. The input file can be an ordinary ASCII, one byte per character text file. A Reader stream automatically translates the characters from the disk file format into the internal char format. The characters in the input file might be from other alphabets supported by the UTF format, in which case there will be up to four bytes per character. In this case, also, characters from the file are translated into char format.

As with output, it is good practice to use a buffer to improve efficiency. Use BufferedReader for this.

BufferedReader stdin = 
    new BufferedReader(new InputStreamReader( System.in ));

These lines create a BufferedReader, but connect it to an input stream from the keyboard, not to a file.