Migration on tsvinc

Spring Boot 4 Keeps a Tracer With Tracing Off

Sun, 25 Oct 2026 00:00:00 +0000

Spring Boot 4.0's release notes cover it in one bullet, under Miscellaneous: "The property management.tracing.enabled has been renamed to management.tracing.export.enabled." The old key doesn't forward to the new one. It doesn't fail startup, and in the run I have it doesn't log a word. Set it to false and it binds to nothing.

I found it while chasing a red test on Boot 4.1.2, and the dead key wasn't what turned the test red. The test was wrong: with the new key, the Tracer bean stays too.

The Build Was Green the Whole Time

Sun, 26 Jul 2026 00:00:00 +0000

12:06. irc-bot, freshly ported from Spring Boot to Micronaut 5.0.6, is committed with fourteen passing tests.
13:35. A test I had just written fails on a class name.
13:56. A sanitiser build of the group's C IRC daemon names the line where it writes to address zero.
19:15. The bot is launched against a real IRC network for the first time. By 19:20 there are three more failures on the list.

Five failures in one afternoon. None of them broke compilation, and none of them tripped a test that existed before I went looking. They turned up because something finally ran: a proxy check, a socket, a live launch.

Upgrade Errors That Named the Wrong Layer

Sun, 26 Jul 2026 00:00:00 +0000

A compiler error is supposed to work like an address. It names a file, a line and a symbol, and the fix lives somewhere near what it names.

One morning in July, five Maven repos put that to the test. They had last been modernized in August 2025, and now all of them needed their frameworks dragged forward at once: Spring Boot 3.4.1 to 4.1.0 in two, Quarkus 3.17.4 to 3.37.4 in one, and two Micronaut projects from 3.x to 5.0.6. The JDK doing the compiling was Temurin 25.0.3. Every pom still targeted Java 17.

Five Things Spring Boot 4.1 Doesn't Tell You Until It's Too Late

Fri, 19 Jun 2026 00:00:00 +0000

Update, 2026-10-19: This post was written before Spring Boot 3.5's open-source support ended on June 30, 2026; the text now states that date in the past tense.

Spring Boot 3.5's open-source support ended on June 30, 2026. Boot 4.0 shipped in November on the Spring Framework 7 baseline, 4.1 is current stable. The migration guide exists and is decent. These are the things it doesn't emphasize enough — discovered porting a 28-API reactive WebFlux app to Spring Boot 4.1.0 on Java 25.