What

A set of internal, behavior-preserving optimizations that reduce web application
deployment/startup time. There are no changes to defaults, configuration,
public API, parsing output, or threading model — outputs are identical; only
redundant work and allocations are removed.

Changes

Annotation / JAR scanning (ContextConfig)

• Index the @HandlesTypes types by name (class-file descriptor form for
  annotations, binary name for classes) so matching a scanned class is an O(1)
  lookup instead of a linear scan of all handled types plus a per-annotation
  string conversion.
• Record whether a fragment JAR contains META-INF/resources/ during the
  annotation scan (which already iterates every entry), so processResourceJARs
  no longer re-opens and re-scans each JAR.
• Check the cached default web.xml freshness with File.lastModified() for
  file: URIs instead of opening a URLConnection.
• Use Collections.singleton for the per-fragment annotation merge.

Mapper (Mapper / batch registration)

• Register a context's servlet mappings into the copy-on-write wrapper arrays in
  a single merge per mapping category instead of reallocating the array once per
  mapping (previously O(n²)). Verified equivalent to the old sequential
  insertMap behaviour (sorted order, existing-wins dedup, wildcard nesting)
  over 300k randomized cases.

Web resources

• JarWarResourceSet: build the META-INF bloom filter once when the entries
  are read rather than rebuilding it on every resource lookup.
• AbstractSingleArchiveResourceSet: pre-size the entry map from the JAR entry
  count.
• StandardRoot: hoist a loop invariant in listResources; Collections.addAll
  instead of Arrays.asList wrapper.

Misc internal

• StandardJarScanner: hoist loop-invariant getJarFileURL()/toURI() out of the
  manifest Class-Path loop; Collections.addAll for the class-path URLs.
• Digester.updateAttributes: resolve the class loader once per call.
• FragmentJarScannerCallback: single map lookup for duplicate detection.
• StandardContext.mergeParameters: iterate entrySet() directly.
• LifecycleBase.fireLifecycleEvent: skip allocating the event when there are no
  listeners.
• AbstractProtocol.init: compute the (built/quoted) name once.
• MbeansDescriptorsIntrospectionSource: Set membership test instead of a
  linear array scan.

Correctness

All changes preserve observable behaviour. The Mapper change was fuzz-checked
against the original sequential implementation (identical arrays and nesting).
TestContextConfigAnnotation is updated to build the new derived index (mirroring
the normal processClasses flow). Please run at least TestMapper*,
TestContextConfig*, and the webresources tests.

Performance

Measured on a build from source (JDK 25), median of 8 start/stop cycles, same
webapp set both sides. The gains scale with application size:

• Mapping-heavy app (~8000 classes, 20000 servlet mappings): server startup
  ~560 ms → ~483 ms (~14%).
• Small/typical apps: low single-digit %, near run-to-run noise.

Changelog entries are included.

Co-Authored-By: Claude Opus 4.8 noreply@anthropic.com