When BufferedReader and StringBuffer is used in java?
Buffered reader is just like Scanner, used to get user input. StringBuffer is used for changeable strings
IO operations are always costlier .Rather than read one character at a time from the network or disk, the BufferedReader reads a large block at a time. That makes it faster. BufferedReader simply reads sequence of characters. StringBuffer is used to create mutable string. As you know String in Java is immutable.