Spring Boot tightens TLS config, docs, and OTLP

Spring Boot landed several reliability fixes that warrant a close look before your next deploy. The documentation now points to the actual security configuration class, removing a reference to the dead SpringBootWebSecurityConfiguration, which had been pointing users toward a class that no longer exists [1]. Also, two resource-leak fixes landed: GsonTester now closes its reader [3], and the SpringBootJoranConfigurator closes a file handle [4]. These are small but eliminate potential file-descriptor exhaustion in test and logback setup paths.

A notable behavior change: SSL host configuration customizations are no longer lost when reloading SSL bundles [2]. Previously, a bundle reload would wipe out host-specific overrides, so any custom trust or key settings per host reverted to defaults. Now they persist across reloads. If you rely on dynamic SSL bundle reloads, this is the one to verify in your test suite.

The OTLP support gained a common configuration for endpoint, compression, and headers [5], and you can now configure Micrometer Tracing MDC keys [6]. Separately, the DataSource root resolution honors a wrapper's unwrap method [7]. Previously, the root DataSource was resolved in a way that ignored the wrapper's unwrap; now the unwrap is honored, which matters when you have custom DataSource wrappers that need to expose the underlying connection pool.

Outside Spring Boot, Spring Batch fixed a null step name that broke JDBC jobs [8]. The fix required adjusting code to keep the Eclipse compiler happy [8]. If you run Spring Batch jobs against a JDBC job repository and use custom step names, check that the step name is never null at the point where the job repository writes it.

Spring LDAP bumped spring-core to 7.0.9 [9], micrometer-bom to 1.17.1 [10], and reactor-core to 3.8.7 [11], among other dependency updates. The repository also added release train workflows [12] and removed tag deployment from branch-level deploy-docs [13]. Spring Integration fixed MailMessageTransformer to not lose headers [14], which matters for mail flows that rely on header propagation.