Choose the Right Java Collection

Java offers you a variety of collection implementations to choose from. In general you will always look for the collection with the best performance for your programming task, which in most cases is ArrayList, HashSet or  HashMap. But be aware, if you need some special features like sorting or ordering you may need to go for a special…

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Java ArrayList Example

Java ArrayList class is a resizable array that implements the List interface. It permits all elements, including null and also implements all optional list operations. Most operations that can be run on ArrayList such as size, isEmpty, get, set, iterator and listIterator are all constant time. However, the add operation’s complexity is O(n) time. Compared to LinkedList, the…

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Java LinkedHashSet Example

LinkedHashSet class in Java differs from HashSet as its implementation maintains a doubly-linked list across all elements. This linked list defines the iteration ordering which is the order in which the elements were inserted into the set. It is called an insertion-order. If an element is re-inserted into the set, the insertion order is not affected by…

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Java LinkedHashMap Example

LinkedHashMap is a combination of hash table and linked list that implement the Map interface with predictable iteration order. The difference between HashMap and LinkedHashMap is that LinkedHashMap maintains a doubly-linked list which allows scanning through all of its entries back and forth. The order is maintained, meaning the order in which keys were inserted…

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