Specific difference between bufferedreader and filereader

I would like to know the specific difference between BufferedReader and FileReader.

I do know that BufferedReader is much more efficient as opposed to FileReader, but can someone please explain why (specifically and in detail)?

In simple manner:

A FileReader class is a general tool to read in characters from a File. The BufferedReader class can wrap around Readers, like FileReader, to buffer the input and improve efficiency. So you wouldn't use one over the other, but both at the same time by passing the FileReader object to the BufferedReader constructor.

Very Detail

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 three 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. This is the same class we've been using for keyboard input. These lines should look familiar:

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.

Source: http://www.oopweb.com/Java/Documents/JavaNotes/Volume/chap84/ch84_3.html