The Open-Closed Principle and Lots of podcast

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The #106 episode with Lincoln Baxter III (@lincolnthree) about:
writing business Java applications, design patterns discussion, code abstractions, Java Server Faces, the simplicity of Java EE 5, PrettyFaces, PrettyTime and enjoying Magic
is available for

CyberJUG-HH: Why is everybody talking about Quarkus?

In this (Why is everybody talking about Quarkus?) Java User Group Hamburg (CyberJUG-HH) session I highlighted possible reasons for Quarkus' popularity, explained Quarkus' optimisation tricks, the differences between Jakarta EE / J2EE / Java EE application servers and Quarkus, discussed the role of MicroProfile and Jakarta EE, migrated a Java EE application to Quarkus, performed multiple deployments, decompiled some code, measured memory consumption and finally cross compiled the Java service to native code using GraalVM:

Payara, the Unknown protocol: RFB and the Solution

Macs are using port 5900 for screen sharing, often also used by video conferencing software like Skype or Microsoft Teams.

Payara uses the same port 5900 for the hazelcast grid as starting port. At collision, payara won't start and complain with:

[#|...|WARNING|Payara 5.201|com.hazelcast.nio.tcp.TcpIpConnection|_ThreadID=108;_ThreadName=hz._hzInstance_1_development.IO.thread-in-1;_TimeMillis=1600401135525;_LevelValue=900;|
[...]:4900 [development] [3.12.6] Connection[id=5, /...:63015->/...:5900, qualifier=null, endpoint=[...]:5900, alive=false, type=NONE] closed. 
Reason: Exception in Connection[id=5, /...:63015->/...:5900, qualifier=null, endpoint=[...]:5900, alive=true, type=NONE], thread=hz._hzInstance_1_development.IO.thread-in-1
java.lang.IllegalStateException: Unknown protocol: RFB
    at com.hazelcast.nio.tcp.UnifiedProtocolDecoder.onRead(
    at com.hazelcast.internal.networking.nio.NioInboundPipeline.process(
    at com.hazelcast.internal.networking.nio.NioThread.processSelectionKey(
    at com.hazelcast.internal.networking.nio.NioThread.processSelectionKeys(
    at com.hazelcast.internal.networking.nio.NioThread.selectLoop(
    The DAS was stopped    


  1. Disable screen sharing in "System Preferences->Sharing->Screen Sharing" or:
  2. Change Payara's port by replacing in $PAYARA_HOME/glassfish/domains/domain1/domain.xml the line <hazelcast-runtime-configuration></hazelcast-runtime-configuration> with <hazelcast-runtime-configuration start-port="59000"></hazelcast-runtime-configuration>. Now Payara will use the port 59000 instead of 5900

Serverless Java #slideless -- Guild42 Session Recordings

The live, on-stage hacking Guild42 session "Serverless Java #slideless" featuring:,, and several Java (openJDK) and native (GraalVM) deployments to AWS Lambda is available:

Setup, Creation and System Test / Black Box Test of a Jakarta EE + MIcroProfile Application in 5 mins

Creating, deploying and testing a Jakarta EE / MicroProfile application with the MicroProfile / Jakarta EE Essentials Archetype and in 5 mins:

Blogs, Quarkus, Service Meshes, Kubernetes, MicroProfile, Neo4J, openJ9, podcast

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The #105 episode with Sebastian Daschner (@daschners) about:
building blog engines, Quarkus, service mesh use cases, kubernetes' maturity, reasons for Jakarta EE and MicroProfile enjoyment, Neo4J, graph databases use cases, openJ9, AsciiDoc, markdown and features of the IBM cloud
is available for

Architectural Frameworks, Java on Mac, JPA vs. JDBC, Encoding, Metrics and OpenTracing, Kafka TX, RolesAllowed Testing--78th

78th event with 20+ questions and topics like:

"Java on RaspberryPI, Quarkus Hackathlon, the state of architectural frameworks, Java on Mac, JPA vs. JDBC, encoding, metrics and OpenTracing, code review, document databases, testing RolesAllowed, kafka and JPA, transaction monitoring, exception handling" published:

Any questions left? Ask now: and get the answers at the next

Future episodes and online events are also going to be also announced at: Airhacks Meetup Group.

Jakarta EE / MicroProfile Maven Archetype with System Tests Support

The 0.0.7+ version of the Jakarta EE / MicroProfile essentials archetype:

mvn archetype:generate \
    -DarchetypeGroupId=com.airhacks \
    -DarchetypeArtifactId=jakartaee-essentials-archetype \

...generates a microservice with corresponding system test.

The following command:

mvn archetype:generate \
    -DarchetypeGroupId=com.airhacks \
    -DarchetypeArtifactId=jakartaee-essentials-archetype \
    -DarchetypeVersion=0.0.7 \
    -DgroupId=com.airhacks \
    -DartifactId=duke \

...creates the duke (Java 11, Jakarta EE 8, MicroProfile 3 based) microservice, as well as, the module duke-st containing the System- / Black Box tests.

The system tests are accessing the microservice via the Rest Client for MicroProfile API and JUnit 5.

Autumn 2020: Upcoming Online JUGs, Conferences and Workshops

  1. Vom Java-Entwickler zum Webguru in 60 Minuten #slideless [online event]
    livecoding session 9 Sep 2020
  2. Jakarta EE and MicroProfile: a Kickstart with reasonable Practices [online event]
    livecoding session 9 Sep 2020
  3. Kickass Java Micro Backends #slideless [online event]
    livecoding session 11 Sep 2020
  4. Kickass Single Page Apps #slideless [online event]
    livecoding session 11 Sep 2020
  5. Serverless Java #slideless [online event]
    livecoding session 14 Sep 2020
  6. "Warum spricht (fast) jeder über Quarkus"? [online event]
    JUG live coding 17 Sep 2020
  7. Architecting and Designing Java, MicroProfile and Jakarta EE Applications [online event]
    live, interactive, virtual workshop 24 Sep 2020
  8. MicroProfile Health, Metrics and Fault Tolerance Implementation Strategies #slideless [online event]
    prerecorded session 13 Oct 2020
  9. Live Virtual MicroProfile on Kubernetes Hacking #slideless [online event]
    prerecorded session 14 Oct 2020
  10. MicroProfile with Quarkus [online event]
    live, interactive, virtual workshop 10 Dec 2020
  11. Micro Frontends with Web Components, lit-html and redux, December [online event]
    live, interactive, virtual workshop 11 Dec 2020

For additional, also free, events like e.g., checkout:

Online Workshops
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