All posts by admin

Working with nested Maps in JAVA

In this post I will show you a simple and easy way of working with JAVA Maps, more precisely, how to add an element (a.k.a value) to a multi nested maps:

That’s it. Simple, isn’t it? 😉

Source code: github

Builder Design Pattern

Here is the “usual” implementation of this design pattern.

 

The result is:
builder2

UML
builder2_uml

 

 

Builder Design Pattern (simple way)

This design pattern allows us to create an object with the advantage that the same construction process can create different representations of that object. Here is the simplest implementation of this design pattern.

In a next tutorial we will explain the other way of doing the same thing, with more flexibility but with a more complex implementation.

So, let’s start creating a car!

 

The final result:

builder

Singleton Design Pattern

With his design patttern we allways get the same instance, as you can see next.

  1. The Singleton class:

 

2. The main class:

 

3. The result:

singleton

 

UML
singleton

Reverse String/array recursively

Here is an example how to recursively invert the order of a string or an array in Java.

The output is:

output

Notice that in the string method we have twice the iterations that we have in the array method, because we go through all positions in the string.

If you know other ways of doing it, please feel free to comment it out.

Thanks.