Java ConcurrentLinkedDeque.offerFirst() is a method in the Java ConcurrentLinkedDeque class that inserts an element at the front of the deque. This method is thread-safe, ensuring that it can be used safely in concurrent environments. Introduced in Java 2004 with Java 5, offerFirst() is commonly used in multi-threaded systems for adding elements to the front of a deque.

https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/ConcurrentLinkedDeque.html