How do I instantiate a Queue object in java?

Considerations for implementation

When choosing an implementation for the Queue interface, it's essential to ponder a few key factors such as performance and concurrency. Here are a few pointers:

• LinkedList is a good choice for a basic FIFO (First-In-First-Out) Queue.
• ArrayDeque can be a superior choice over LinkedList when concurrent access is not required, thanks to its contiguous memory allocation.
• Turn to PriorityQueue when you need a Queue that sorts its elements.
• For concurrent scenarios, consider thread-safe queues like ConcurrentLinkedQueue or LinkedBlockingQueue.

Performance and concurrency considerations

When LinkedList is your friend:

• Use it for a simple FIFO Queue.
• It's your go-to when no concurrent access, among multiple threads, is required.

When ArrayDeque is the boss:

• It's faster than LinkedList due to its contiguous memory allocation.
• It can serve as a Stack (Last-In-First-Out) or Queue (First-In-First-Out) helping you keep your options open.

In concurrent environments:

• ConcurrentLinkedQueue provides a non-blocking thread-safe queue.
• LinkedBlockingQueue is ideal when you need blocking functionality, for instance, threads waiting for the queue to become non-empty or for space in case the queue is full.

Avoid pitfalls, use it right

Common errors to beware of:

• Attempting to instantiate an interface like so: Queue<String> queue = new Queue<>() will get you a trip down CompilationError route. Queue is an interface and cannot be instantiated directly.

Play safe with Queue operations:

• Favor offer(), peek(), and poll() over add(), element(), and remove() to safely interact with the Queue and avoid exception gymnastics.

Traversing a Queue:

• for-each or Iterators are your allies in traversal.
• In adventures of peeking or polling, always have your guards up and check if the Queue isn't lonely (empty).

Advanced implementations

Specialized behavior anyone?

• Look towards LinkedTransferQueue or PriorityBlockingQueue for specialized behavior and firmer control in concurrent applications.

Making your Queue

• To customize a Queue, extend an AbstractQueue and implement the methods, this way, you get to tailor your Queue, if you like playing god.
• Alternatively, anonymous inner classes can provide on-the-fly implementations, (useful in unit tests).

Interface and its contract:

• The Queue interface is a blueprint. However, the concrete class implementing the interface is responsible for adhering to the contract for the expected behavior. Do study the specific implementation's documentation.