Java Archives - Page 10 of 32

Ankur in Java

Jakarta EE 11 for Spring Developers: What Actually Matters

If you write Spring for a living, “Jakarta EE 11” sounds like somebody else’s problem: application servers, EJBs, a different world. Yet every Spring Boot 4 application already runs on pieces of it — the servlet API under the web server, the persistence API under Hibernate, the validation API under @NotNull. When Jakarta EE 11 shipped, most of it arrived in your project without a headline. This article separates what actually changed in those pieces from what merely got a new number. It does that by reading the real API jars — EE 10 next to EE 11 — and Spring Boot’s own version list, rather than the marketing summary. You only need to know that Jakarta EE is a family of standard Java APIs and that Spring uses several of them. Versions and status. Spring Boot 4.1.1 (Spring Framework 7.0.9, Tomcat 11.0.24, Hibernate 7.4.5), JDK 25.0.4, Maven 3.9. Jakarta jars compared: Servlet 6.0.0→6.1.0, Persistence 3.1.0→3.2.0, Validation 3.0.0→3.1.0, Annotations 2.1.1→3.0.0, Concurrency 3.0.0→3.1.1, plus Data 1.0.2. Companion code: spring-boot-demo/jakarta-ee-11.

Ankur in Java

Automating javax → jakarta and Boot 3 → 4 Upgrades with OpenRewrite

Every Spring team eventually faces the same afternoon: change javax. to jakarta. in four hundred files, rewrite the security configuration, rename a dozen properties, and then do it again for the next major version. It is dull, error-prone work, and it is exactly what a tool called OpenRewrite is for. OpenRewrite reads your source into a tree, applies recipes — small, named, repeatable edits — and writes the result back, formatting intact. You run it as a Maven plugin. This article runs it for real on a deliberately old application, shows every line it changed, and, more usefully, lists what it left for you. You need to know what Maven is and what a Spring Boot upgrade involves; nothing about OpenRewrite. Versions and status. rewrite-maven-plugin 6.46.1, rewrite-spring 6.37.1, rewrite-migrate-java 3.42.1. Legacy app: Spring Boot 2.7.18 on JDK 17.0.20, Maven 3.9. Recipes moved it to Boot 3.5.16 and then 4.0.8; I bumped the last step to 4.1.1 by hand. One legacy application with one test is a demonstration, not a survey — your codebase will find things this one does not. Companion code: spring-boot-demo/openrewrite.

Ankur in Hibernate

Hibernate 8 and Jakarta Persistence 4.0 Preview: What Will Break

A 205-test Hibernate suite run against Hibernate 8.0.0.Beta3 and Jakarta Persistence 4.0.0-M7: the classpath trap, the Spring blocker, removed APIs, a binary-compatibility break and the runtime changes that did and did not reproduce. Preview article, updated at GA.

Ankur in Java

Spring Boot 4.2 Preview: AMQP 1.0, Buildpack Image Cache and What to Test Now

Spring Boot 4.2.0-M2 run next to 4.1.1: the spring-boot-starter-amqp name that changes protocol, RestTemplate deprecated for removal, the forwarded-header default that flips, the buildpack image cache and what to test first. Preview article, updated at GA.

Ankur in AI & Machine Learning

Writing Custom Advisors in Spring AI 2.0: Logging, PII Redaction and Token Budgets

Write Spring AI 2.0 advisors for logging, PII redaction and token budgets, and learn why advisor order and streaming decide what your logs and memory see.

Ankur in AI & Machine Learning

Chat Memory in Spring AI 2.0: JDBC, Redis and Windowed Conversations

A chat model forgets everything between calls. This article shows how Spring AI 2.0 chat memory works, and what its JDBC and Redis repositories, the message window, and concurrent requests do that the defaults do not tell you, run against real PostgreSQL 16 and Redis Stack.

Ankur in Java

JDK 27 Memory Changes: Compact Object Headers by Default and G1 Everywhere (JEP 534 + 523)

JDK 27 makes compact object headers and G1 the defaults everywhere. Measured on a Spring Boot 4.1 service with JDK 25, 26 and 27: 15% smaller live set, which classes shrink, real cgroup container sizing, and the flags that stopped working.

Ankur in Java

Lazy Constants in JDK 27 (JEP 531): Replacing Double-Checked Locking

Java's LazyConstant (JEP 531, third preview in JDK 27) against the holder idiom and double-checked locking: the API run on JDK 25, 26 and 27, the failure rule that changed between 26 and 27, List, Map and Set.ofLazy, a JMH benchmark, and why it is not yet for shipped code.

Ankur in Java

Sealed Classes and Interfaces in Java: Modelling Domains with Exhaustive switch

Sealed classes and interfaces in Java, verified on JDK 21, 25 and 27: permits and the three modifiers, six compile errors, why an exhaustive switch should have no default, generic and recursive hierarchies, the visitor comparison, JVM enforcement, modules, and Jackson 3 polymorphism.

Ankur in Java

Pattern Matching in Java: switch, Record Patterns and Primitive Patterns (JDK 21 to 27)

Java pattern matching from JDK 21 to 27, verified on three JDKs: type patterns, switch guards, record patterns, sealed exhaustiveness and the MatchException that separate compilation can still cause, null and unnamed patterns, and JEP 532 primitive patterns (preview).