Adapter Design Pattern in Java

Adapter design pattern is a structural design pattern that provides two unrelated interfaces to work together. The most common illustration about adapter design pattern is sockets from different countries. Well most of us faced with laptop adapter issues when traveling, and looked for appropriate adapter for our laptops. So, by using an adapter we are […]

Create Qualifiers for CDI Beans

As I described in my previous post, we can define and inject cdi beans by @Named annotation. Well according to the CDI specification (JSR-299) injecting beans by their names is legacy and tend to cause issues (if a bean is tried to be injected by an undefined/wrong name then we will get errors which are […]

Convert objects to/from JSON by Jackson example

We will see a simple example about converting objects to/from JSON objects in Java by Jackson. First, add maven dependency for jackson.

And two typical Person and Address classes. Person.java

Address.java

Notes @JsonCreator annotation is used for constructors or static factory methods to construct instances from Json. This is called property base […]

Arquillian Example for CDI Dependency Injection

Arquillian is a platform which provides integration tests by deploying, running containers so that we can easily use cdi beans in tests. In this tutorial we will see how to inject and use cdi beans in test classes by running Arquillian. As a first step we have to add Arquillian core library in our pom.xml […]

Java CDI Dependency Injection Example

CDI (Context and Dependency Injection) is a specification defined in JSR-299. Major aim is loose coupling by dependency injection.In this tutorial we will see how to use CDI Dependency Injection in java with three different ways; Field injection Constructor injection Setter method injection We are going to use @Inject alongside @Named annotations from CDI of […]

Graphs

Graphs are data structures to represent road networks, the web, social networks etc. Moreover, hundreds of computational problems are related to graphs.They have two main ingredient which are; as known as nodes. : pair of vertices can be undirected. or directed. When we are talking about of a graph, notation refers to a graph which […]

Quicksort

Quicksort is a sorting algorithm which applies divide and conquer paradigm. Quicksort has a worst case running time of , however, it has running time of on average which makes quicksort very efficient. Moreover, it works in-place but not stable. The performance of quicksort depends on selecting the pivot, and starting to partition around it. […]

Selection Sort

Selection sort is an in-place comparison sort algorithm which has running time complexity in both best and worst case. Even though its logic is similar to insertion sort, it’s a very inefficient sorting algorithm. List is both divided into two parts as sorted and unsorted where initially sorted part is empty. Every turn, algorithm finds […]

Merge Sort

Merge sort is another comparison based sort algorithm. It closely follows divide-and-conquer paradigm, and provides run time complexity in worst and average cases, however, in space complexity. Merge sort can be used for sorting huge data sets that can not fit into memory. It is also a stable sort which preserves the order of equal […]

Binary Search

Binary search is a searching algorithm which works on a sorted (ascending or descending) array. In each turn, the given key is compared with the key at the middle of the array, if it is equal to it then its index is returned. Otherwise, if the given key is less than key at the middle […]