list adts and the collections framework in this sectionwe discuss general list adtswhich combine methods of the dequearray listand/or node list adts before describing such adtswe mention larger context in which they exist the java collections framework java provides package of data structure interfaces and classeswhich together define the java collections framework this packagejava utilincludes versions of several of the data structures discussed in this booksome of which we have already discussed and others of which we discuss in the remainder of this book in particularthe java util package includes the following interfacescollectiona general interface for any data structure that contains collection of elements it extends java lang iterablehenceit includes an iterator(methodwhich returns an iterator of the elements in this collection iteratoran interface for the simple iterator adt listan interface extending collection to include the array list adt it also includes method listiterator for returning listiterator object for this list listiteratoran iterator interface that provides both forward and backward traversal over listas well as cursor-based update methods mapan interface for mapping keys to values this concept and interface are discussed in section queue