MongoDB 3 array query operations are very helpful and simplify digging in nested structures. In this post we’ll show how to create queries that match array elements in various ways.
Towers of Hanoi recursive version
Towers of Hanoi is a well known puzzle, very often used to teach recursion. In this post we will show how to solve this puzzle recursively.
Top 10 sites to practice programming
Java read XML using DOM
Java read XML using DOM
Java DOM API is comfortable to work with not big XML documents. They can be easily loaded and modified in runtime. In this post we show how to do it.
Java create XML using DOM
Java create XML using DOM
Java allows to work with XML in many different ways. In this post we show how to use Java DOM API to create a document and write it as XML file.
Prime numbers – Sieve of Eratosthenes in Java
Prime numbers – Sieve of Eratosthenes
A prime number is a natural number with only two divisors: 1 and itself.
In this post we’re going to show how to find prime numbers using Sieve of Eratosthenes and explain how it works.
Java Singleton – enum implementation
Java Singleton – enum implementation
Singleton as enum is very simple to implement and very safe at the same time thanks to language guarantees for enum instantiation and serialization.
Java Singleton – on demand initialization
Java Singleton – on demand initialization
On demand initialization is extension of static final implementation. It will prevent eager initialization of the singleton instance, when other fields are accessed. Also known as Bill Pugh‘s solution.
Java Singleton – static final implementation
Java Singleton – static final implementation
It is the simplest and most common implementation of Singleton Design Pattern in Java. In this post we’ll show how to implement it correctly and explain why it works.
Java CyclicBarrier – game simulation
Java CyclicBarrier is very convenient synchronization tool for writing concurrent simulations. In this post we’ll show how it works and write a game simulation.
