The regular expressions are available in the package which has many classes but the most important are Pattern. A HashMap however, store items in ' key / value ' pairs, and you can access them by an index of another type (e.g. The regular expressions are character sequences that can be used to match other strings using a specific pattern syntax. Java HashMap In the ArrayList chapter, you learned that Arrays store items as an ordered collection, and you have to access them with an index number ( int type). Now in order to sort a hash map according to the values mapped to its corresponding keys we first need to get all values of map. All the words that start with a can be found in a string by using regular expressions in Java. As we know that Hash map in Java does not maintain insertion order either by key or by order.Also it does not maintain any other order while adding entries to it. Step 1 : Create one HashMap object called wordCountMap which will hold words of the input file as keys and their occurrences as values.

The regular expressions are character sequences that can be used to match other strings using a specific pattern syntax. Sorting a HashMap according to values in Java. All the words that start with a can be found in a string by using regular expressions in Java.

Hashmap of all words in dictionary java