[2748109647]

Fixes #1289.

When rebuilding CuratorCache, avoid issuing getChildren for a node whose Stat reports zero children. The recursive persistent watcher is registered before rebuilding, so children created after this check are still delivered as watcher events.

Adds a regression test that initializes the cache with empty nodes and verifies that a child created afterward is observed.

Validation:

• ./mvnw -pl curator-recipes -am -Dtest=TestCuratorCache -Dsurefire.failIfNoSpecifiedTests=false test — passed (6 tests).
• ./mvnw -pl curator-recipes spotless:check — passed.
• git diff --check — passed.

The full reactor and a large-tree performance benchmark were not run; no quantified performance improvement is claimed.

[2748109647]

Thanks for the CI signal. I checked run #39507194896: Unit tests (17) failed before Maven started, at ./mvnw clean install -DskipTests, with Could not find or load main class org.apache.maven.wrapper.MavenWrapperMain. The wrapper JAR is intentionally ignored and absent from a clean checkout; this job's wrapper bootstrap did not leave a usable JAR. The other Java/ZooKeeper jobs and the style check passed. The Maven Central wrapper JAR URL currently returns HTTP 200, which suggests a transient bootstrap/download failure, though the quiet wrapper log does not expose its exact cause. I tried rerunning failed jobs, but GitHub requires repository admin rights. Could a maintainer rerun the Java 17 job? The failure happened before compilation, so I have no source change to push for it.