Rustam Mehmandarov

@mehmandarov
457 Followers
159 Following
149 Posts
Passionate computer scientist | Java Champion | Google Developer Expert (GDE) for Cloud | Docker Captain | Public speaker | Community builder | Ex-leader of JavaZone and Norwegian JUG – javaBin.
Twitterhttps://twitter.com/RMehmandarov
Websitehttps://mehmandarov.com
GitHubhttps://github.com/mehmandarov
Follow me everywhere @ rustam.nohttps://rustam.no
Rustam Mehmandarov1d ago

🎉 New blog post!

Extra JSON fields in REST responses: ignored or error?

It depends. JSON-B, Jackson, #Quarkus, and #SpringBoot do not all behave the same.

Inspired by a question at J-Spring in Utrecht.

https://mehmandarov.com/unknown-json-fields-in-java-rest-clients/

#Java #JakartaEE #MicroProfile

Unknown JSON fields in Java REST clients: JSON-B, Jackson, Quarkus, and Spring Boot

What happens when a JSON response contains more fields than your DTO declares? The answer depends on your JSON provider. A look at the defaults for JSON-B, Jackson, Quarkus, and Spring when consuming an API with the MicroProfile REST Client – with the official docs to back each one up.

Rustam Mehmandarov
Rustam Mehmandarov4d ago
Can we talk more about all of these things? #programming
Rustam Mehmandarov6d ago

🎉 New blog post: Before writing your own rules parser, have a look at Jakarta Expression Language (EL).

Less parser code, more standard platform. Plus the security work you shouldn't skip: trusted inputs, resolver whitelists, and timeouts.

https://mehmandarov.com/jakarta-el-safer-rules-without-handwritten-predicate-parsers/

#Java #JakartaEE #Security

Jakarta EL: safer rules without handwritten predicate parsers

A practical look at Jakarta Expression Language as a small in-process policy engine – replacing a handwritten predicate parser with jakarta.el.ELProcessor, then hardening evaluation with a resolver whitelist and timeout.

Rustam Mehmandarov
Rustam MehmandarovMay 27

🎉 New Blog Post: Sane API error handling with RFC 9457 Problem Details in Java https://mehmandarov.com/rfc-9457-problem-details-jakarta-ee/

#jakartaee #java #rfc9457 #api #rest

Sane API error handling with RFC 9457 Problem Details in Jakarta EE

A practical look at RFC 9457 Problem Details for HTTP APIs in Jakarta EE – a hand-made ProblemDetail + ExceptionMapper approach, the Zalando Problem library, and a short note on Quarkus and Spring.

Rustam Mehmandarov
Rustam MehmandarovApr 23

🎉 New blog post: API versioning in Java using JAX-RS with Jakarta EE and MicroProfile: https://mehmandarov.com/api-versioning/

#jakartaee #java #microprofile #api

API versioning in Java using JAX-RS with Jakarta EE and MicroProfile

Exploring common API versioning strategies in Java using JAX-RS with Jakarta EE and MicroProfile – URL, header, and media type versioning – with pros, cons, and practical code examples.

Rustam Mehmandarov
Rustam MehmandarovApr 19

I've been working on my Advanced API Design talk with #Java and #JakartaEE since 06:00 AM today.

Just committed the changes while mumbling "No rest for the wicked".

Then it hit me... the talk is literally about #REST. 🤷‍♂️💻

Jokes aside, I can't wait to present this talk again! 🙌

#Programming

Rustam MehmandarovMar 17

Java 26 just got released today! 🥳☕ It was announced here, at JavaOne 2026.

#Java #JavaOne #JavaOne26

Rustam MehmandarovMar 12
François MartinMar 11
Enjoying @mehmandarov's talk at #JavaLand for the second time since I liked it so much when I saw it at the JChampions conference 😊
Rustam MehmandarovMar 11
Next up: First row at the talk by @edburns on #java app modernisation, here at #JavaLand. 👍
Rustam MehmandarovMar 11
Great talk by @mthmulders and @bmarwell on improving #maven build speeds here at #javaland Great job, folks!