Gain insights into Java Collections Framework. Delve into lists, sets, and hashmaps. Learn about data modification, sorting, thread-safety, and internal workings for efficient usage.

Collection is one of the most important topics for Java programming. Without the proper knowledge of every collection type in Java, it becomes difficult for you to decide which option to pick in a particular scenario.

This course will give you a great understanding of all collection types available in the Collections Framework like lists, linked lists, sets, and hashmaps. 

After completing this course, you will know how data can be modified within a collection, how to sort a collection, and how it can be made thread-safe. You will also cover the internal working of each Java collection so you can work with them more efficiently.

Collections in Java

## Fetching an element from a TreeSet
The following methods can be used to fetch elements from a TreeSet.
### Fetching the first element
We can fetch the first element in the **TreeSet** using the `first()` method. If the TreeSet is empty, then `NoSuchElementException` is thrown.

### Fetching the last element
We can fetch the last element in the **TreeSet** using the `last()` method. If the TreeSet is empty, then `NoSuchElementException` is thrown.

### Fetching the subset of elements
We can use the `subSet(E fromElement, E toElement)` method to fetch a subset of **TreeSet** within a given range. This method will return the elements ranging from `fromElement` to `toElement`. Note that `fromElement` is inclusive and `toElement` is exclusive.

### Fetching elements that are smaller than the given element
The `headSet(E toElement)` method returns all the elements that are smaller than the provided element. The `toElement` is not inclusive.

### Fetching elements that are greater than the given element
The `tailSet(E fromElement)` method returns all the elements which are greater than the provided element. The `fromElement` is not inclusive.


# Fetching an element from a TreeSet
The following methods can be used to fetch elements from a TreeSet.
## Fetching the first element
We can fetch the first element in the **TreeSet** using the `first()` method. If the TreeSet is empty, then `NoSuchElementException` is thrown.

## Fetching the last element
We can fetch the last element in the **TreeSet** using the `last()` method. If the TreeSet is empty, then `NoSuchElementException` is thrown.

## Fetching the subset of elements
We can use the `subSet(E fromElement, E toElement)` method to fetch a subset of **TreeSet** within a given range. This method will return the elements ranging from `fromElement` to `toElement`. Note that `fromElement` is inclusive and `toElement` is exclusive.

## Fetching elements that are smaller than the given element
The `headSet(E toElement)` method returns all the elements that are smaller than the provided element. The `toElement` is not inclusive.

## Fetching elements that are greater than the given element
The `tailSet(E fromElement)` method returns all the elements which are greater than the provided element. The `fromElement` is not inclusive.


Let's discuss fetching and removal operations in TreeSet.

Let's Begin

Lists in Java

LinkedList in Java

CopyOnWriteArrayList in Java

Sets in Java

TreeSet in Java

HashMap In Java

TreeMap in Java

LinkedHashMap in Java

Additional Map Implementations

Arrays Class

Collections Class

TreeSet: Fetching and Removal

Fetching an element from a TreeSet

Fetching the first element

Fetching the last element