Previous posts are not available right now due to server maintenance!

This includes a visual representation (graph) paired with a short code example and concise explanations. These bite-sized summaries cover essential concepts that programmers should be familiar with to write more effective Java code.
December 29, 2025

It focuses on the Map<K, V> interface, which does not extend Collection, and has key implementations like HashMap (unordered by hash table), TreeMap (ordered by natural/comparable keys), and LinkedHashMap (order of insertion), as well as specialized interfaces like SortedMap and NavigableMap for ordered functionality, allowing efficient storage of key-value pairs.

The path from Queue to classes that implement this interface will be covered. We'll only see the classes ArrayDeque and PriorityQueue for now. Note that in concurrency, we have ArrayBlockingQueue and PriorityBlockingQueue among others, but they are not within the scope of the current review.

The path of List from interface to classes that implement it. A theoretical review of interfaces and abstract classes is made, until reaching the classes that implement them. Also, some legacy classes are shown, which are no longer recommended for use in new code.

The path of Set to reach classes that implement this interface. A theoretical review of some interfaces, purpose to reach the classes that implement them. For later practice demonstration purposes.

In this post, a quick review of the forEach method for iterating over collections and maps is made, along with a brief tip on when to use it and when not to, and a small reminder that forEach is a terminal operation in Java streams.

This is the start of a series of quick reviews on collections, some classes and interfaces belonging to the Java Collections framework. Interfaces from which come the methods used for iteration in collections. And why an array is not considered a Java collection, from the Collections framework.

Information about licenses of various resources used on this site.

The cookie policy is a legal notice that informs users about the use of cookies and similar technologies.

The privacy policy explains what user data are captured, why, and how they are handled, ensuring transparency and compliance with data protection laws.