question: private static List < Integer > possibleLocations ( String str ) { List < Integer > possibleLocations = new ArrayList < Integer > ( ) ; int lastIndex = - 1 ; int index ; while ( ( index = str . indexOf ( "${" , lastIndex + 1 ) ) >= 0 ) { if ( lastIndex == index ) { break ; } possibleLocations . add ( index ) ; lastIndex = index ; } return possibleLocations ; }
target:  Identifies any possible interpolation locations (begins by looking for "${").