Java: LinkedList offer vs add methods

The LinkedList class in Java provides two methods offer and add to add an element to the list.

There is a subtle difference between both of them.

The add method

The add method is inherited from the List interface. It returns a boolean value to indicate whether the element was successfully added to the list or not.

Also, you will get an IllegalStateException if the list is at its capacity.

The offer method

The offer method is defined in the Queue Interface. It was added to the Queue interface in Java 1.5

It returns a boolean value indicating whether the element was successfully added to the queue or not.

offer method will return a boolean false if the queue is at its capacity instead of an exception.

Method	Interface	Returns	Exception	When to Use
add(e)	List	boolean	IllegalStateException if the list is full	Using the LinkedList as a List to check if the element was successfully added
offer(e)	Queue	boolean	boolean false if the queue is full	Using LinkedList as a Queue or for interchanging implementations of the Queue interface