Quick Start; Spring Security 5 OAuth2 Login


Social logins using Oauth2 have become a industry standard. It revolutionized the way sites share data and has allowed users to quickly access new applications without having to create a new set of credentials. This article gives an example of why OAuth2 was invented as well as provides a working example of Spring Security 5 application integrated with Google.

The source code for this tutorial is available on Github.

But what did sites do before OAuth2?

Before OAuth2, sites did some pretty scary things to get users data from other applications. For example; requiring your login credentials to get your contacts from another application. The classic example of this is Yelp in 2008 where they would ask for your login credentials to gather your contacts from MSN, Yahoo, AOL, and Gmail. This was a huge security risk because it meant you were giving your password to Yelp, and they were promising they wouldn’t do anything bad to your account.

Example of Yelp before OAuth2

But how is OAuth2 going to solve this problem?

Have you ever created an account on a site using your Facebook, Google, or Microsoft account? These are examples of OAuth2 client providers. Using one of these providers we can register our application to allow user sign ins with their existing email accounts, while at the same time not compromising the user. Essentially we are offhanding all the authentication to the client provider.

With Spring Security 5 this process could not be more simple to implement. In this quickstart tutorial we will see how to quickly setup a spring boot app to use Spring Security 5 to authenticate users with Google.

Begin by creating a new Spring Boot project. Because we want this to have a restful interface I am including the “Spring Web” dependencies and of course the “Spring Security” dependency as this gives us the OAuth2 client libraries. I am using version 2.2.6.RELEASE for the example;


<!-- oauth2 -->


I also include swagger dependencies. Swagger is a tool that lets you document your api endpoints. It comes with a nice user interface, and you will see us using this later on to test restful endpoints.


Creating an app in Google Cloud

Now that we have all our dependencies setup we must register our application within the provider (Google Cloud); Google OAuth2 implementation follows the OpenID Connect 1.0 specification which is an identity layer added to the protocol and allows clients to verify the identity of the end-user based on the authentication performed by the authorization server. It provides basic profile information about the end-user.

To authenticate users you must create a new application within the Google Cloud Platform. If you don’t have an account yet, quickly sign up for one. Then navigate to the “API & Services” -> “Credentials” section to generate “OAuth 2.0 Client Ids”. For this example I am making this an internal api, which only allowing users within my organization to authenticate. I have also set the authorized redirect URI of “http://localhost:5000/login/oauth2/code/google”.

Registering a new Oauth client within Google cloud

After creation you should receive an appId and secret key.

Using the newly generated clientId create a Oauth2LoginConfig class within our app.

public class OAuth2LoginConfig {

    public static class OAuth2LoginSecurityConfig extends WebSecurityConfigurerAdapter {

        protected void configure(HttpSecurity http) throws Exception {
            http.authorizeRequests(authorize -> authorize.anyRequest().authenticated())

    public ClientRegistrationRepository clientRegistrationRepository() {
        return new InMemoryClientRegistrationRepository(this.googleClientRegistration());

    public OAuth2AuthorizedClientService authorizedClientService(
            ClientRegistrationRepository clientRegistrationRepository) {
        return new InMemoryOAuth2AuthorizedClientService(clientRegistrationRepository);

    public OAuth2AuthorizedClientRepository authorizedClientRepository(
            OAuth2AuthorizedClientService authorizedClientService) {
        return new AuthenticatedPrincipalOAuth2AuthorizedClientRepository(authorizedClientService);

    private ClientRegistration googleClientRegistration() {
        return CommonOAuth2Provider.GOOGLE.getBuilder("google")

This class configures a does several things;

  • Creates a WebSecurityConfigurerAdapter which secures all restful endpoints.
  • Registers a ClientRegistrationRepository and Oauth2AuthorizedClientService both using there respective in memory services / respositories. This means that the app will store all user data in memory once logged in.
  • The highlight of this class is the google client registration at the bottom. Using the api key and api secret from our google cloud account update the missing variables. This DSL also configures scopes which we will request from Google. The user must approve the scopes to give us access to there profile information

This configuration uses a DSL setup, but you can easily configure the google client registration using a yml file as well.

What is DSL?

DSL stands for domain specific language or also referred to as a fluent interface based on the builder pattern. You can see this by how the chaining together configuration options for the “http security” and “client registration”.

Creating a secure api

At this point the application is ready to run. But we want to see the results of our authenication with Google. Create a simple SecureController and output the results of the OAuth2User within the spring application.

public class SecureController {

            value = "Get the current logged-in user",
            notes = "This example only returns the user logged in from Google")
    public HashMap<String, Object> index(@ApiIgnore @RegisteredOAuth2AuthorizedClient OAuth2AuthorizedClient authorizedClient,
                                         @ApiIgnore @AuthenticationPrincipal OAuth2User oauth2User) {
        HashMap<String, Object> results = new HashMap<>();
        results.put("username", oauth2User.getName());
        results.put("attributes", oauth2User.getAttributes());
        results.put("authorities", oauth2User.getAuthorities());
        results.put("clientScopes", authorizedClient.getClientRegistration().getScopes());
        results.put("clientName", authorizedClient.getClientRegistration().getClientName());
        return results;

What is this RegisteredOAuth2AuthorizedClient and AuthenticationPrincipal?

The RegisteredOAuth2AuthorizedClient annotation resolves to a Oauth2AuthorizedClient which we have registered in our application using the OAuth2LoginConfig class above. In this case it will be Google, which it will resolve to our registered client that has our public and private key. The Oauth2AuthorizedClient also contains the access token, refresh token, and client registration with the user scopes we have requested.

The AuthenticationPrincipal holds our currently authenticated user within the application. It has attributes pretaining to the OpenId 1.0 specification such as name, profile, picture, email, birthdate, etc. which are all consider standard claims.

Swagger Config

Finally, create a SwaggerConfig class to register our rest controller location

public class SwaggerConfig {

    public Docket api() {
        return new Docket(DocumentationType.SWAGGER_2)

Running the application

Launch the Spring Boot 2.0 app and go to http://localhost:8080/swagger-ui.html. You are then redirected to a Google for authentication.

After you have authenticated with your google account credentials, the next page will ask you to consent to your app having access to the Oauth Client registered in your Google Cloud account. Clicking allow will authorize our spring boot app to access the users email and basic profile information as identified in our scopes from the ClientRegistration.

Once consent has been granted you will be redirected back to the swagger-ui page. Execute the secure controller get request to see your authenticate user.

The application currently sets a cookie for an authorized user using a default session called JSESSIONID. This session is tied to our authenicated user within the application. If I were to restart the application the in-memory store is lost. Meaning I would have to log back into the application again.

Wrap Up

Today this article showed how to quickly get up and running with Spring Security 5 OAuth2. The app integrates with Google to allow for a secure authentication and consent of users with a google account. The applications API was secured using a session token which is generated using the Spring Security 5.3 OAuth2 libraries.

Source code can be found on Github.

Optimizing your application using Spring Boot 2.x and Amazon ElastiCache for Redis


Has your project gotten to the point when big data sets and or time consuming calculations begin to affect performance? Struggling to optimize your queries and need to cache some information to avoid continually hitting your database? Then caching could be your solution.

For this article I will demonstrate how to utilize Amazon ElastiCache for Redis to speed up areas of your application. The exmple application we will build uses Spring Boot 2.x and is available on Github.

What is Amazon ElastiCache for Redis?

ElastiCache for Redis is a super fast, in memory, key-value store database. It supports many different kinds of abstract data structures, such as strings, lists, maps, sets, sorted sets, hyperloglogs, bitmaps and spatial indexes. At its highest level, ElastiCache for Redis is an fully managed service for a standard Redis installation and uses all the standard Redis API’s. Which means the app we are building can rely not only on the Amazon ElastiCache flavor of Redis, but any other environment matching the version of your choosing.

Setting up ElastiCache for Redis

Begin by navigating to the ElasticCache dashboard, selecting Redis, and create a new cluster. You will be prompted to define a cache name, description, node type (server size), and number of replicates.

I filled in the name, description, and changed the node type to a smaller instance.

VPC & Security Groups

To be able to access your Redis cluster the instance(s) running our app must have be in the same Virtual Private Network (VPC) and contain the proper security groups. Your EC2 instances must allow the port of your redis cluster (6379) to be able to communicate. By default your Redis cluster is only accessible internally from the VPC selected. This is done purposely, as no internet gateway should be connected as it would defeat the purpose of a high efficiency, in-memory cache that Redis provides. 

Our app will only be able to access Redis once it is deployed to AWS.

If you wish to run the app locally, consider installing Redis using docker. The variables outlined in our application.properties file below can be modified to run locally.

Launching your Redis Cluster

Once your have properly configured your security groups and VPC, click “create”. ElastiCache will now provision and launch you new Redis cluster. When the status turns to available the cluster is ready to handle connections.

We need the primary endpoint for our new spring boot application.

Building our application

For this example application we will be using Spring Boot 2.x with the Spring-Data-Redis and Jedis (client library for redis). I first begin by importing them into my project


These  libraries allow us to setup our caching config in Spring. A important concept to understand is that the Spring Framework provides its own abstraction for transparently adding caching. You do not only have to use Redis, the abstraction provides a list of providers; CouchbaseEhCache 2.xHazelcast, etc. As you will see adding caching to a service method is as simple as providing the appropriate annotation.

Now that we have included the required libraries in our pom file, Spring will try to autoconfigure a RedisCacheManager. I personally do not like magic behind the scenes so we are going to setup and configure our own annotation based RedisCacheManager. 

A RedisCacheManager is how we configure, and build a cacheManger for Spring to use. Notice that I have defined the redisHostName, redisPort, and redisPrefix for the Jedis (client library for redis) to use to connect to our cluster.

public class RedisConfig {

private String redisHostName;

private int redisPort;

private String redisPrefix;

JedisConnectionFactory jedisConnectionFactory() {
RedisStandaloneConfiguration redisStandaloneConfiguration = new RedisStandaloneConfiguration(redisHostName, redisPort);
return new JedisConnectionFactory(redisStandaloneConfiguration);

@Bean(value = "redisTemplate")
public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory redisConnectionFactory) {
RedisTemplate<String, Object> redisTemplate = new RedisTemplate<>();
return redisTemplate;

@Bean(name = "cacheManager") // Default cache manager is infinite
public CacheManager cacheManager(RedisConnectionFactory redisConnectionFactory) {
return RedisCacheManager.builder(redisConnectionFactory).cacheDefaults(RedisCacheConfiguration.defaultCacheConfig().prefixKeysWith(redisPrefix)).build();

@Bean(name = "cacheManager1Hour")
public CacheManager cacheManager1Hour(RedisConnectionFactory redisConnectionFactory) {
Duration expiration = Duration.ofHours(1);
return RedisCacheManager.builder(redisConnectionFactory)

I have defined 2 cache managers. One that is infinite (default), and once that will cause all keys to expire in 1 hour called “cacheManager1Hour” .

The cluster information is passed in from the applications.properties:


Implementing a simple service

Now that our Redis cluster is configured in Spring, annotation based caching is enabled. Let’s assume you have a long running task that takes 2 seconds to do its work. By annotation the service with @Cacheable the result of the method call will be cached. I have given this cachable a value of “getLongRunningTaskResult” which will be used in its compound key, a key (by default is generated for you), and a cacheManager (“cacheManager1Hour” configured above).

@Cacheable(value = "getLongRunningTaskResult", key="{#seconds}", cacheManager = "cacheManager1Hour")
public Optional<TaskDTO> getLongRunningTaskResult(long seconds) {
try {
long randomMultiplier = new Random().nextLong();
long calculatedResult = randomMultiplier * seconds;
TaskDTO taskDTO = new TaskDTO();
Thread.sleep(2000); // 2 Second Delay to Simulate Workload
return Optional.of(taskDTO);
} catch (InterruptedException e) {
return Optional.of(null);

Note: It is important that the resulting object of the method is serializable otherwise the cacheManager will not be able to cache the result.

Testing for performance improvements

To easy test the API, I have included swagger-ui which make it simple for developers to interact with the api we have built. I have also created a few simple endpoints to create, and flush the cache.

value = "Perform the long running task")
@RequestMapping(value = "/{seconds}", method = RequestMethod.GET)
public ResponseEntity<TaskDTO> longRunningTask(@PathVariable long seconds) {
Optional<TaskDTO> user = taskService.getLongRunningTaskResult(seconds);
return ResponseUtil.wrapOrNotFound(user);

value = "Resets the cache for a key")
@RequestMapping(value = "/reset/{seconds}", method = RequestMethod.DELETE)
public ResponseEntity<?> reset(@PathVariable long seconds) {
return new ResponseEntity<>(HttpStatus.ACCEPTED);

Once you deploy your app to EC2 navigate to URL path: /swagger-ui.html

From this GUI you can easily test your API performance improvements. Calling the GET endpoint for the first time should take roughly 2 seconds to return the new calculated result. Calling it subsequently will return an almost instant response as the long running task is now cached in Redis.

Final thoughts

Today’s applications demand a responsive user experience, design your queries and calculations to be as performant as possible, but every once in awhile when you can sacrifice real time data, just cache it.

Full project code is available at: https://github.com/sixthpoint/spring-boot-elasticache-redis-tutorial

Quickstart AWS SQS + Spring Boot Processing FIFO Queues


AWS SQS (Simple Queue Service) can provide developers with flexibility, and scalability when building microservice application(s). In this quickstart tutorial it demonstrates how to configure a FIFO queue for a fictional online marketplace.

The code for this application is available on Github.

What is a FIFO queue?

A FIFO (First in first out) queue is used when the order of items or events is critical, or where duplicates items in the queue are not permitted. For example;

  • Prevent a user from buying an item that isn’t available on a marketplace.

Configuring AWS

This tutorial assumes you have an AWS account already created. Begin by creating a SQS queue call PendingOrders.fifo in a region of your choice with content-based deduplication enabled. Each queue has its own unique URL.

The format of this URL is https://sqs.<region>.amazonaws.com/<account_id>/<queue_name>. Take note of this URL, as it will need it to run the application (Set this in a SIXTHPOINT_SQSURL environment variable). You can see the URL for your SQS in the details screen of SQS in AWS console or by using the aws cli command aws sqs list-queues. Please see Figure 1 for reference.

Figure 1: PendingOrders.fifo created with Content-Based Deduplication enabled

Content-Based Deduplication:

FIFO queues do not allow for duplicate messages. If you retry to send an identical message within the 5 minute deduplication interval, the message will be tossed out. This assures that your messages will be processes exactly once. So by enabling this feature AWS SQS uses a SHA-256 hash to generate the deduplication ID using the body of the message; Not the attributes of the message.

This is useful for our simple example because our message payload will contain only a itemCount which is the total number of items they are buying, and a requestTime which is the epoch time the order was received.

The Application

The sample application is composed of a single OrderProcessingService which is stateful. This service handles submitting the order to the queue, as well as listening for orders via the @SqsListener annotation.

Creating an order

To create an order a PendingOrder class is written to a single json string. The default client for AmazonSQSClientBuilder is then used to send a message to the queue.

public void createOrder(int itemCount) {
try {
PendingOrder pendingOrder = new PendingOrder();
String pendingOrderJson = configProperties.getObjectMapper().writeValueAsString(pendingOrder);

final AmazonSQS sqs = AmazonSQSClientBuilder.defaultClient();
sqs.sendMessage(new SendMessageRequest(configProperties.getSqsURL(), pendingOrderJson).withMessageGroupId("sixthpointGroupId"));

} catch (final AmazonClientException | JsonProcessingException ase) {
log.error("Error Message: " + ase.getMessage());

The PendingOrder contains an itemCount which is the total number of items they are trying to purchase, and a requestTime. Since we are using content-based deduplication this means that no more than 1 request can be done per second with the same itemCount.

Processing the queue

Using the @SqsListener annotation the application checks the PendingOrders.fifo periodically to process pending items. An item is read in and mapped using the object mapper. The availableItems is either decremented by the supplied pendingOrder count or an error logged for no more items remaining.

private int availableItems = 5;

public void process(String json) throws IOException {
    PendingOrder pendingOrder = configProperties.getObjectMapper().readValue(json, PendingOrder.class);
    if(availableItems > 0 && availableItems >= pendingOrder.getItemCount())
        availableItems = availableItems - pendingOrder.getItemCount();
        log.info("Items purchased, now have {} items remaining", availableItems);
    } else {
         log.error("No more items are available");

Wrap up

This article quickly shows how to setup and configure your first AWS SQS FIFO queue using Spring Boot.

Full code with configurable environment variables can be found on

Using Docker + AWS to build, deploy and scale your application


I recently worked to develop a software platform that relied on Spring Boot and Docker to prop up an API. Being the only developer on the project, I needed to find a way to quickly and efficiently deploy new releases. However, I found many solutions overwhelming to set up.

That was until I discovered AWS has tools that allow any developer to quickly build and deploy their application.

In this 30 minute tutorial, you will discover how to utilize the following technologies:

Once finished, you will have a Docker application running that automatically builds your software on commit, and deploys it to the Elastic beanstalk sitting behind a load balancer for scalability. This continuous integration pipeline will allow you to worry less about your deployments and get back to focusing on feature development within your application.

Here is the order in which to configure services:

  1. Git repository initialization using CodeCommit
  2. CodeBuild Setup
  3. EBS Configuration
  4. CodePipeline Configuration
Background knowledge

I am using Docker for this tutorial application. However AWS supports a wide range of configurable environments in the Elastic beanstalk; .NET, Java, NodeJS, PHP, Python, Ruby. Docker was chosen for this tutorial so that the reader can focus more on the build process and less on the project setup. With that being said, I will not be diving deeply into Docker. If you wish to learn more about Docker, start by reading the introduction on the Docker website.

The Application

The example Spring Boot source code that will be used can be found at: https://github.com/sixthpoint/Docker-AWS-CodePipeline

The application is a Spring Boot project configured to run on port 5000 and has a REST controller with a single endpoint.

The API REST controller is very basic. It maps /api/ path to a method which returns a list of strings in JSON format. This is the endpoint we will use to verify our application has successfully built and deployed on the AWS EBS.

@RequestMapping( value = "/api" )
public class ApiController {

    @RequestMapping( value = "/", method = RequestMethod.GET )
    public List<String> index() {
        List<String> s = new ArrayList<>();
        s.add("Docker + AWS CodePipline Tutorial");
        s.add("Learn more at: https://github.com/sixthpoint/Docker-AWS-CodePipeline");
        return s;

The application creates am example-1.0.0-SNAPSHOT.jar file when built using Maven. This file is important for us to reference in our Dockerfile.

Maven build:
mvn clean install

Would produce target/example-1.0.0-SNAPSHOT.jar. The Dockerfile below uses a flavor of Alpine Linux to add, expose and run the Spring Boot application.

FROM openjdk:8-jdk-alpine
ADD target/example-1.0.0-SNAPSHOT.jar app.jar
ENTRYPOINT [ "sh", "-c", "java $JAVA_OPTS -Djava.security.egd=file:/dev/./urandom -jar /app.jar" ]
1. Git repository initialization using CodeCommit

First things first, we need a git repository to build our code from. AWS CodeCommit is cheap, reliable, and secure. It uses S3 which is a scalable storage solution subject to S3 storage pricing.

Begin by logging into your AWS console and creating a repository in CodeCommit. For the purpose of this tutorial, I have called the repository name the same name as the Spring Boot application. Once created, you will be presented with the standard HTTPS and SSH URLs of the repository.

The above example has generated the following repository location, notice if I try to do a clone from the repository access is denied.

git clone https://git-codecommit.us-east-1.amazonaws.com/v1/repos/DockerCodePipleline

The above example has generated the following repository location; notice if I try to do a clone from the repository, access is denied.


IAM or Identity and Access Management enables you to securely control access to AWS services and resources. To authorize a user to access our private git repository, navigate to the IAM services page. Begin by adding a user. I have named the user the same name as the project and git repository. Choose programmatic access which will allow for policies to be added.

In order to allow this new user to fully administer our new git repository, attach the AWSCodeCommitFullAccess policy. Once added, click through to finish creating your user.

Now that a user has been created with the correct policies, GIT credentials are needed to work with the new CodeCommit repository. Navigate to the new user and look for the “HTTPS Git credentials for AWS CodeCommit” shown below. Generate a new username and password and download the .gitCrendientialsfile once prompted. Inside that file is the information needed to access your repository.

Note: Only two keys are allowed per user at this time. If you lose your key, a new one will need to be generated to access the repository. For more in-depth information on setting up git credentials in AWS, check out the guide for setting up HTTPS users using Git credentials.


With the new repository created, clone the Github repository holding our sample Spring Boot application. Change the remote to your new CodeCommit repository location, then finally push the master branch to master.

git clone https://github.com/sixthpoint/Docker-AWS-CodePipeline.git
git remote set-url origin git://https://git-codecommit.us-east-1.amazonaws.com/v1/repos/DockerCodePipleline
git push master master
2. CodeBuild Setup

Now that the CodeCommit repository holds our sample Spring boot application, the code needs to be built for deployment. Navigate to CodeBuild. CodeBuild is a source code compiler which is pay on demand.

Start by creating a new build project and point the source to the AWS CodeCommit repository that was created in Step 1. You can see I have pointed this new build project to the AWS CodeCommit source provider, and specified the DockerCodePipeline repository.

Next it asks for environmental information. The default system image is fine for this build process. The most important part is to tell CodeBuild to use the buildspec.yml. The buildspec contains the necessary commands to generate the artifacts needed to deploy to the EBS.

Included in the sample Spring Boot application is a buildspec.yml. This file is used to tell CodeBuild what commands to run in each phase, and what files to bundle up and save in the artifacts.

Additional configuration options can be found at: http://docs.aws.amazon.com/codebuild/latest/userguide/build-spec-ref.html.

version: 0.2

      - mvn clean
      - mvn install
    - 'Dockerfile'
    - 'target/example-1.0.0-SNAPSHOT.jar'

Final setup for the build process is to specify the location where the artifact made from the buildspec.ymlwill be stored. In the example below, I put all artifacts in the Amazon S3 under the name dockerAWSCodePipeline, and in a bucket named irdb-builds. The bucket can be in bucket of your choice. You must go into S3 and create this bucket prior to creating the build project.

The build project is now configured and ready to use. Builds can manually be run from the console creating artifacts stored in S3 as defined above.

4. EBS Setup

Now that the code is in CodeCommit, and the artifacts are built using CodeBuild, the final resource needed is a server to deploy the code. That is where the Elastic beanstalk comes in useful. The EBS is a service that automatically handles provisioning, load balancing, auto-scaling, etc. It is a very powerful tool to help your manage and monitor your applications servers.

Let’s assume, for example, my API needs to have four servers due to the amount of requests I am receiving. The EBS makes the scaling of those servers simple with configuration options.

Begin by creating a new webserver environment and give it a name and domain name. This domain name is your AWS domain name; if you have a personal domain name you can point it to this load balancer being created using Route53.

The last step of creating your webserver worker environment is to tell EBS that we want to run Docker and to use the example application code. Later our code from CodeBuild will replace the AWS sample application.

The server and environment will take several minutes to start. Once complete, navigate to the configuration page of your new EBS environment.

By default the environment has a load balancer installed and auto scales. A scaling trigger can be set to adjust the number of instances to run given certain requirements. For example: I could set my minimum instances to 1 and maximum to 4 and tell the trigger to start a new instance each time the CPUUtilization exceeds 75%. The load balancer would then scale requests across the number of instances currently running.

5. CodePipeline Configuration

This is the final piece of the puzzle which brings all steps 1-4 above together. You will notice that up until now we have had to manually tell CodeBuild to run, then would have to go to the EBS and manually specify the artifact for deployment. Wouldn’t it be great if all this could be done for us?

That is exactly what Codepipeline does. It fully automates the building and provisioning of the project. Once new code is checked in, the system magically takes care of the rest. Here is how to set it up.

Begin by creating a new CodePipeline. In each step. select the repository, build project, and EBS environment created in step 1-4 above.


Once complete the CodePipeline will begin monitoring changes to your repository. When a change is detected, it will build the project, and deploy it to the available servers in your EBS application. You can monitor the CodePipeline in real time from the pipelines detail page.

A Final Word

When configured properly, the CodePipeline is a handy tool for the developer who wants to code more and spend less time on DevOps.

This pipeline gives a developer easy access to manage a application big or small. It doesn’t take a lot of time or money to set yourself up with a scalable application that utilizes a quick and efficient build and deployment process.

If you are in need of a solution to build, test, deploy, and scale your application, consider AWS CodePipeline as a great solution to get your project up and running quickly.


Multiple Beans are Eligible for Injection


In some cases you may want to inject a controller (another backing bean) into another controller. In Eclipse it will show a warning: Multiple beans are eligible for injection to the injection point. This may prevent your server from starting.

The solution is to provide CDI with the name of the property to inject. The @Named annotation is shown below:

private MyController myController;

Now CDI will know the proper controller to inject.

How to skip Maven unit tests


All Maven unit tests are ran by default. When a test fails the project will not build. While this forces you to have a stable build of your project before deploying; it may not be ideal in some situations.

Skipping Over Failed Unit Tests

Within the in maven-surefire-plugin in your pom, specify the skipTests parameter


Now all tests will be skipped on the next build.

Using a comparator to sort 2 separate instances


Consider you have 2 separate classes; “dog” and “cat”. Both of these classes share a common interest in that they are animals. Each of these animals have a date of birth. In this example I will demonstrate how to merge 2 object arrays of both types (“dog” and “cat”) and sort them by their common property; date of birth.

Where might I need this?

In the case of needing both cats and dogs on the same dataTable in JSF this would provide a merged object array to iterate through.

The Code

Creating the abstract class “animal” to be extended by both the dog and cat classes. This abstract class defines what both a cat and dog have in common; a name.

public abstract class Animal {

     * All animals must have a name
    protected String name;

    public abstract String getName();

    public abstract void setName(String name);


Both the cat and dog classes are very similar. For the purpose of this tutorial they both only have a date of birth.

public class Cat extends Animal {

    private Date dob;

    public Cat(String name, Date dob) {

    public Date getDob() {
        return this.dob;

    public void setDob(Date date) {
        this.dob = date;

    public String getName() {
        return this.name;

    public void setName(String name) {
        this.name = name;


The dog class is identical to the cat class.

public class Dog extends Animal {

    private Date dob;

    public Dog(String name, Date date) {

    public String getName() {
        return this.name;

    public void setName(String name) {
        this.name = name;

    public Date getDob() {
        return this.dob;

    public void setDob(Date date) {
        this.dob = date;


The Solution

To sort both cats and dogs by date of birth first begin by creating a list of each type then adding a few objects to each. The code below adds 2 animals to each type. Then all objects are added to a list of object array. Using collection.sort comparator it checks which type of object is being passed. It then casts that object to its instance type and gets the date of birth. The final statement in the method is the compareTo function which compares the date of birth for each type. Using this approach you can see that you could easily add additional object array types and sort them all by a common date.

 List <Cat> cats = new ArrayList <> ();
 cats.add(new Cat("Chester", new Date(105, 9, 4)));
 cats.add(new Cat("Peaches", new Date(105, 8, 1)));

 List <Dog> dogs = new ArrayList <> ();
 dogs.add(new Dog("Willie", new Date(115, 2, 4)));
 dogs.add(new Dog("Buster", new Date(89, 3, 4)));

 List <Object> objects = new ArrayList <> ();


 Collections.sort(objects, new Comparator <Object> () {@
     public int compare(Object m1, Object m2) {
         Date d1 = null;
         Date d2 = null;

         if (m1 instanceof Cat) {
             d1 = ((Cat) m1).getDob();
         } else {
             d1 = ((Dog) m1).getDob();

         if (m2 instanceof Cat) {
             d2 = ((Cat) m2).getDob();
         } else {
             d2 = ((Dog) m2).getDob();

         return d1.compareTo(d2);

 for (Object o: objects) {
     if (o instanceof Cat) {
         System.out.println("Name: " + ((Animal) o).getName() + " DOB: " + ((Cat) o).getDob());
     } else {
         System.out.println("Name: " + ((Animal) o).getName() + " DOB: " + ((Dog) o).getDob());

The following code is available on Github.

JSF detect session timeouts with web filter


When working with JSF 2.0 you will encounter a situation in which the user’s session times out and ajax requests fail. The response on a ajax request will be a viewExpiredException. However, the root cause is the session has expired. They are essentially stuck on the page and are forced to reload.

The solution:

Using a WebFilter the user can gracefully be redirected to a view expired exception page. This solution is accomplished by checking if the users session is valid, and if the context path is within our required conditions, finally if it is a ajax request it overwrites the default JSF response with our own custom xml response that tells the browser to redirect to the view expired exception page.

@WebFilter(filterName = "SessionTimeoutFilter", urlPatterns = "*.jsf")
public class SessionTimeoutFilter implements Filter {

    private final String timeoutPage = "/errors/viewExpired.xhtml";

    private final String loginPage = "/login.jsf";
    public void destroy() {

    public void doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain) throws IOException,
    ServletException {

        if (request instanceof HttpServletRequest && response instanceof HttpServletResponse) {
            HttpServletRequest httpServletRequest = (HttpServletRequest) request;
            HttpServletResponse httpServletResponse = (HttpServletResponse) response;

            if (isRequireSessionControl(httpServletRequest) && isSessionInvalid(httpServletRequest)) {

                if (isAJAXRequest(httpServletRequest)) {
                    StringBuilder sb = new StringBuilder();
                    sb.append("<?xml version=\"1.0\" encoding=\"UTF-8\"?><partial-response><redirect url=\"")
                        .append(httpServletRequest.getContextPath() + timeoutPage).append("\"></redirect></partial-response>");
                    httpServletResponse.setHeader("Cache-Control", "no-cache");
                    PrintWriter pw = response.getWriter();

                httpServletResponse.sendRedirect(httpServletRequest.getContextPath() + timeoutPage);
        filterChain.doFilter(request, response);

    public void init(FilterConfig filterConfig) throws ServletException {

    private boolean isAJAXRequest(HttpServletRequest request) {
        boolean check = false;
        String facesRequest = request.getHeader("Faces-Request");
        if (facesRequest != null && facesRequest.equals("partial/ajax")) {
            check = true;
        return check;

    private boolean isRequireSessionControl(HttpServletRequest httpServletRequest) {
        String requestPath = httpServletRequest.getRequestURI();
        return !requestPath.contains(timeoutPage) && !requestPath.contains(loginPage)
                        && !requestPath.contains("javax.faces.resource");

    private boolean isSessionInvalid(HttpServletRequest httpServletRequest) {
        return httpServletRequest.getRequestedSessionId() != null && !httpServletRequest.isRequestedSessionIdValid();

Note: This fix is required due to a bug that is set to be resolved in JSF 2.3 release: https://java.net/jira/browse/JAVASERVERFACES_SPEC_PUBLIC-790

2 way encryption with MD5 DES


Data encryption standard (DES) is a old way of encrypting data. It effectively encrypts data to a unreadable string; however it should be noted that it is not secure. The following code is for demonstration purposes only and should not be implemented as a security protocol. DES is a breakable algorithm smaller key, and block size than a advanced encryption standard (AES) algorithm.

Use case

A user is prompted to enter some non sensitive data. For the sake of this example lets assume we have a requirement that the user telephone number must be encrypted. The user enters a phone number and the encode method secures the data for storage in the database. Upon rendering back to the end user the data is translated using the decode method.

public class MD5andDES {

    // A user chosen password used for the PEKeySpec. Once set do not change or all previously encoded data will be lost
    private static final char[] PBEKeyPassword = "nviowefjklaasdlkjweklnvq".toCharArray();

    // Private salt for PBE algorithm
    private static final byte[] PBESALT = {(byte) 0xde, (byte) 0x33, (byte) 0x10, (byte) 0x12, (byte) 0xde, (byte) 0x33, (byte) 0x10, (byte) 0x12};

     * Takes in a string which is then salted with a given password used for the
     * 2 way encryption
     * @param data
     * @return
     * @throws GeneralSecurityException
     * @throws UnsupportedEncodingException
    public static String encode(String data) throws GeneralSecurityException, UnsupportedEncodingException {

        // Get algorithm to use
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("PBEWithMD5AndDES");

        // Generates a secretKey object from the provided key specification
        SecretKey key = keyFactory.generateSecret(new PBEKeySpec(PBEKeyPassword));

        // Returns a cipher object that implements the specified transformation
        Cipher pbeCipher = Cipher.getInstance("PBEWithMD5AndDES");

        // Initializes cipher with public key
        pbeCipher.init(Cipher.ENCRYPT_MODE, key, new PBEParameterSpec(PBESALT, 20));

        // Returns the cipher encoded to a 64bit string (aka base64 encoded). getBytes() forms a new byte array
        return DatatypeConverter.printBase64Binary(pbeCipher.doFinal(data.getBytes("UTF-8")));

     * Takes in encrypted data and uses the salt to decrypt it to its original
     * state
     * @param data
     * @return
     * @throws GeneralSecurityException
     * @throws IOException
    public static String decode(String data) throws GeneralSecurityException, IOException {

        // Get algorithm to use
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("PBEWithMD5AndDES");

        // Generates a secretKey object from the provided key specification
        SecretKey key = keyFactory.generateSecret(new PBEKeySpec(PBEKeyPassword));

        // Returns a cipher object that implements the specified transformation
        Cipher pbeCipher = Cipher.getInstance("PBEWithMD5AndDES");

        // Initializes cipher with public key
        pbeCipher.init(Cipher.DECRYPT_MODE, key, new PBEParameterSpec(PBESALT, 20));

        // Returns a string of the orignally encrypted data
        return new String(pbeCipher.doFinal(DatatypeConverter.parseBase64Binary((data))), "UTF-8");


A complete working copy with test cases is available for checkout on Github.

BufferedImage JPEG transparency using OpenJDK


When attempting to write a transparent JPEG to disk using OpenJDK 5,6,7 javax.imageio.IIOException error is thrown. This occurs because OpenJDK does not have a native JPEG encoder. There are two separate solutions.

Solution 1: Change the library

A alternative would be to switch from OpenJDK to Sun’s JDK which has a native JPEG encoder.

Solution 2: Buffered image write around

A programmatic way to solve the problem is to map or draw the existing BufferedImage onto a new BufferedImage with the type changed from TYPE_4BYTE_ABGR (default) to TYPE_3BYTE_BGR (new). The converted image will now be writable to disk.

// Read in the uploaded file
InputStream input = file.getInputstream();
BufferedImage originalImg = convertInputStreamToBufferedImage(input);

// Converts the buffered image to the required type then draws the original on top
BufferedImage convertedImg = new BufferedImage(originalImg.getWidth(), originalImg.getHeight(), BufferedImage.TYPE_3BYTE_BGR);
convertedImg.getGraphics().drawImage(originalImg, 0, 0, null);

// Write to disk
ImageIO.write(convertedImg, "jpeg", new File("/PATH/filename.jpg"));