Dear Checkstyle

I am not a big fan of forced styles and all these errors that comes with it.

I know, I know… If you are on a team of more people, you don’t have much of a choice otherwise you end up with style chaos and naming convention that are closer to a standup comedian number than logic.

I am just not a big fan…

We have a style for the member name in our classes that only allows for letters and number but I did a class to match the json returned from Azure OIDC so it is all lowercase name with underscore. Checkstyle would not let this through so I learned quickly how to turn that off for my class

This is the module in Checkstyle:

<module name="SuppressionCommentFilter">
    <property name="offCommentFormat" value="CHECKSTYLE.OFF\: ([\w\|]+)"/>
    <property name="onCommentFormat" value="CHECKSTYLE.ON\: ([\w\|]+)"/>
    <property name="checkFormat" value="$1"/>

All you have to do is a comment:


and after my class definition I can simply turn it back on:

// CHECKSTYLE.ON: MemberName

Then I could discuss with a team mate and disagree about having an annotation (@jsonproperty(“name_with_underscore”)) for each member name to respect the checkstyle and work with the json. What is the simplest will always win in my mind and not following made up rules for the sake of the rule.

Automating Keycloak with Java

We needed to automate some tasks in our Keycloak so that some elements were created as events were happening.

I find that the Java library for Keycloak is not always intuitive. It does not help that my searches for the documentation or examples returned all sorts of contradicting results.

In this case adding an Identity Provider seems to have many ways to be done but only 1 worked for me.

What works:


Alternative code I had seen that I could not get to work for me:

var clientRes = client.updateRealm(destinationRealmResource.toRepresentation());

And this did not work for me:

var clientRes = client.updateRealm(destinationRealmResource.toRepresentation());

This was done with Keycloak 15.

In my troubleshooting I also noticed that having some invalid strings in your representation configuration can cause the creation to fail. I am not a fan of the Map<String, String> for the configuration because that leaves room for a lot of mistakes.

Breaking istio in microk8s

I was running microk8s version 1.20 on my laptop and decided to upgrade it to 1.22 since it is the newest stable version.

That was easy:

sudo snap refresh microk8s --channel=1.22/stable

After the upgrade I noticed that many applications in the istio-system were not working. I taught that deleting the pod would recreate it and fix the issue but they kept failing.

When I try to remove istio I get an error:

sudo microk8s.disable istio
Disabling Istio
Error: unknown flag: --purge

And I am stuck in this state.

I have not found any solution to this yet.

MS Team for Linux

Where is the configuration for my credentials?

That is how I started my day because I wanted to use my Ubuntu laptop today. I started team and it was clearly trying to login to my previous employers account. Infinite loop that probably guarantees my ip to be flagged.

After a few DuckDuckGo searches I could not find anything other than the trivial guides to install the snap on Ubuntu.

I tried looking at the file system and I was not able to figure out where the credentials are configured.

So… I cleared all the caches to start fresh and it worked well enough to get me going.

cd snap/teams-for-linux
rm -Rf 172
rm -Rf 182
rm -Rf current

The 172 and 182 where the running directories in my case but I assume that you might have different numbered directories based on your running environment/version.

After starting Team, it has recreated the 182 directory and current symlink.

Dependency Hell

It is not a secret even if we try to hide from it.

The dependencies in writing any application today is a nightmare and a lot of work to maintain straight.

Google has a tool to look at some open-source project and as much as it is not the first of such tool, I like the graph mode available.

I was trying to find something interesting to look at but most java projects I looked at had simple graphs. I found this one that makes the tool visual shine a bit:

Interesting tool.

Keycloak Identity Provider ID

That took a couple of hours to figure out so let’s share some notes.

I have code that creates the required Keycloak Realms and configures a few items in each of them.

One of those configuration is to create the Identity Provider so that we can link users to another realm. Internal SSO if you will.

I tested this with Keycloak 11.0.3.

I did not understand that the Identity Provider ID needed to be one of the specific values since it is only a string that you pass to it. Sometimes I wish they could use an enum to help users make sense of it quickly.

After getting errors that it was a required fields and trying a few values that did not make sense to Keycloak.

10:39:07.587 [main] DEBUG org.apache.http.wire - http-outgoing-0 << "{"errorMessage":"Invalid identity provider id [password]"}"

10:41:50.814 [main] DEBUG org.apache.http.wire - http-outgoing-0 << "{"errorMessage":"Invalid identity provider id [EmailAuthProviderID]"}"

I tried keycloak-oidc and it worked. So the value needs to be one of these:

  • saml
  • oidc
  • keycloak-oidc

You could also use one of the social identity provider.

I also understood to take the config from the endpoint:

Sample code:

IdentityProviderRepresentation identityProviderRepresentation = new IdentityProviderRepresentation();
Map<String, String> config = new HashMap<>();
config.put("issuer", "");
config.put("authorization_endpoint", "");
config.put("token_endpoint", "");
config.put("introspection_endpoint", "");
config.put("userinfo_endpoint", "");
config.put("end_session_endpoint", "");
config.put("jwks_uri", "");
config.put("check_session_iframe", "");
config.put("grant_types_supported", "[\"authorization_code\",\"implicit\",\"refresh_token\",\"password\",\"client_credentials\"]");
config.put("response_types_supported", "[\"code\",\"none\",\"id_token\",\"token\",\"id_token token\",\"code id_token\",\"code token\",\"code id_token token\"]");
config.put("subject_types_supported", "[\"public\",\"pairwise\"]");
config.put("id_token_signing_alg_values_supported", "[\"PS384\",\"ES384\",\"RS384\",\"HS256\",\"HS512\",\"ES256\",\"RS256\",\"HS384\",\"ES512\",\"PS256\",\"PS512\",\"RS512\"]");
config.put("id_token_encryption_alg_values_supported", "[\"RSA-OAEP\",\"RSA1_5\"]");
config.put("id_token_encryption_enc_values_supported", "[\"A256GCM\",\"A192GCM\",\"A128GCM\",\"A128CBC-HS256\",\"A192CBC-HS384\",\"A256CBC-HS512\"]");
config.put("userinfo_signing_alg_values_supported", "[\"PS384\",\"ES384\",\"RS384\",\"HS256\",\"HS512\",\"ES256\",\"RS256\",\"HS384\",\"ES512\",\"PS256\",\"PS512\",\"RS512\",\"none\"]");
config.put("request_object_signing_alg_values_supported", "[\"PS384\",\"ES384\",\"RS384\",\"HS256\",\"HS512\",\"ES256\",\"RS256\",\"HS384\",\"ES512\",\"PS256\",\"PS512\",\"RS512\",\"none\"]");
config.put("response_modes_supported", "[\"query\",\"fragment\",\"form_post\"]");
config.put("registration_endpoint", "");
config.put("token_endpoint_auth_methods_supported", "[\"private_key_jwt\",\"client_secret_basic\",\"client_secret_post\",\"tls_client_auth\",\"client_secret_jwt\"]");
config.put("token_endpoint_auth_signing_alg_values_supported", "[\"PS384\",\"ES384\",\"RS384\",\"HS256\",\"HS512\",\"ES256\",\"RS256\",\"HS384\",\"ES512\",\"PS256\",\"PS512\",\"RS512\"]");
config.put("claims_supported", "[\"aud\",\"sub\",\"iss\",\"auth_time\",\"name\",\"given_name\",\"family_name\",\"preferred_username\",\"email\",\"acr\"]");
config.put("claim_types_supported", "[\"normal\"]");
config.put("claims_parameter_supported", "false");
config.put("scopes_supported", "[\"openid\",\"offline_access\", \"profile\",\"email\",\"address\",\"phone\",\"roles\",\"web-origins\",\"microprofile-jwt\"]");
config.put("request_parameter_supported", "true");
config.put("request_uri_parameter_supported", "true");
config.put("code_challenge_methods_supported", "[\"plain\",\"S256\"]");
config.put("tls_client_certificate_bound_access_tokens", "true");

Finally, I have creation of the Identity Provider in my realm and I can link users to it.

No JDK 16 for Gradle 6

That was an annoying configuration where my project was using JDK 11 but I did not see that my Gradle settings were using JDK 16 and that kept giving me the error:

Caused by: org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:

After I removed JDK 16 from my project, it pointed me to the fact that Gradle had no JDK configured. Hint.

Now that everything is using JDK 11, life is beautiful again in my IDE.

Development Software Management

I have used a simple tool for many years to manage the development software I need on my Linux workstation:

The installation is very simple has highlighted on their home page:

curl -s "" | bash

A bit scary to be running a script that you download straight into a shell but you can do as you see fit to examine the script first if you prefer.

I use it to install Java, Gradle, Kotlin, Spark, VisualVM and it allows you to try a few other framework. You can even decided which Java vendor you want to use.

A big advantage is that it installs all these software in your home directory and it does not affect the system. You can also quickly switch from a version to another and that has proven very useful more than once.

Quick Installation of K8S

The tutorials out there to install Kubernetes on your workstation are great but I simply need a quick series of steps. This is to install Micro-K8S on a Ubuntu workstation.

sudo snap install microk8s --classic

I also create a few aliases because typing the entire commands is a bit long

sudo microk8s kubectl get all -A


vi .bash_aliases

alias kgaa='sudo microk8s kubectl get all -A'
alias kga='sudo microk8s kubectl get all'
alias kg='sudo microk8s kubectl get'
alias kp='sudo microk8s kubectl get pods'
alias kn='sudo microk8s kubectl get ns'
alias kd='sudo microk8s kubectl describe'

source .bash_aliases

A Brave Browser

With all the tracking that exists today, I have been looking at minimizing what all these big corporations are collecting about me. There are many ways to do this but I decided to try the Brave browser.

It is easy to install on Ubuntu from these instructions:

Only a few commands:

sudo apt install apt-transport-https curl gnupg

curl -s | sudo apt-key --keyring /etc/apt/trusted.gpg.d/brave-browser-release.gpg add -

echo "deb [arch=amd64] stable main" | sudo tee /etc/apt/sources.list.d/brave-browser-release.list

sudo apt update

sudo apt install brave-browser

It is done in less than 2 minutes.

The first time I ran Brave I changed the default search engine to be so that I am closing another door on the tracking.

I have been using it for a few weeks and I am very happy.

It is always interesting to see the number of items that have been blocked. There is a lot of tracking going on (obviously).