list lambda treeMap

1. Lambda: A lambda expression is a concise way to represent a function that can be passed around as an argument to other functions or methods.

2. TreeMap: A TreeMap is a collection that stores key-value pairs in a sorted order based on the natural ordering of the keys or a custom Comparator.

3. map: The map method in Java applies a given function to each element of a collection and returns a new collection with the transformed elements.

4. filter: The filter method in Java returns a new collection with elements that satisfy a given predicate.

5. reduce: The reduce method in Java applies a given function to the elements of a collection and returns a single value that represents the result of the operation.

6. flatMap: The flatMap method in Java takes a collection of collections and flattens it into a single collection.

7. forEach: The forEach method in Java applies a given function to each element of a collection.

8. stream: The stream method in Java creates a stream of elements from a collection, which can be used to perform various operations on the elements.

9. sorted: The sorted method in Java returns a sorted collection based on the natural ordering of the elements or a custom Comparator.

10. collect: The collect method in Java collects the elements of a stream into a collection.