question: private Matcher reset ( CharSequence input , int start , int end ) { if ( input == null ) { throw new IllegalArgumentException ( "input == null" ) ; } if ( start < 0 || end < 0 || start > input . length ( ) || end > input . length ( ) || start > end ) { throw new IndexOutOfBoundsException ( ) ; } this . input = input . toString ( ) ; this . regionStart = start ; this . regionEnd = end ; resetForInput ( ) ; matchFound = false ; appendPos = 0 ; return this ; }
target:  Resets the Matcher. A new input sequence and a new region can be specified. Results of a previous find get lost. The next attempt to find an occurrence of the Pattern in the string will start at the beginning of the region. This is the internal version of reset() to which the several public versions delegate.