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java.util.LinkedHashMap stores Key Value pairs like java.util.HashMap, and enables the retrieval of a Value given a Key. LinkedHashMap differs from HashMap in that the Keys are ordered by their insertion order. LinkedHashMap maintains a double-linked list to determine insertion order.
This tutorial, complete with an easy to understand and interactive UML visualization, explains how LinkedHashMap works.
java.util.TreeMap stores Key Value pairs like java.util.HashMap, and enables the retrieval of a Value given a Key. TreeMap differs from HashMap in that the Keys are ordered by their natural order. Internally the TreeMap maintains a Tree data structure, used to order and locate keys.
This tutorial, complete with an easy to understand and interactive UML visualization, explains how TreeMap works.
If you were asked in an interview: “What types of bean injection are there in Spring”. What would your answer be?
There are two types of bean injection in Spring: Setter-based dependency injection (DI) and Constructor-based dependency injection…
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Why is a Java Semaphore useful? Today I’ll tell you the four reasons why a Java Semaphore is useful.
When attempting to retrieve a value from a Map which doesn’t exist, often it is desirable for the Map to provide an initial value. This saves the developer adding in extra logic to detect, create and insert the initial value. Java 8 adds a new Map method… [Read more…]
Providing a good implementation of java.lang.Object::hashCode, is essential to HashMap performance.
This tutorial, complete with a source code visualization, describes how HashMap performance can be improved…
The Java collection class, java.util.HashMap enables the storage of Key Value pairs. Given a Key, the HashMap enables the associated Value to be efficiently retrieved.
This tutorial, complete with an easy to understand UML visualization, explains how HashMap works.
Concurrency in non-trivial systems is difficult. java.util.concurrent. CountDownLatch is one of my favourite concurrent core Java classes, because it simplifies the synchronization of threads. This class is useful when you want to wait until some task in another thread completes, before continuing in the current thread.
