question: @ Override public String toString ( ) { StringBuilder sb = new StringBuilder ( ) ; sb . append ( String . format ( "%d " , firstZero ) ) ; for ( int i = 0 ; i < Math . max ( INITIAL_LENGTH , bits . length ( ) ) ; i ++ ) { sb . append ( bits . get ( i ) ? "x" : "." ) ; } return sb . toString ( ) ; }
target:  Pretty-prints the coverage vector, making a guess about the length