Use tailMap for O(matches) wildcard key iteration instead of O(totalKeys)

[Copilot]

Wildcard expansion was scanning the entire map.keySet() for every existingEntry, making each lookup O(totalKeys) regardless of how many keys actually matched.

Changes

• tailMap-bounded iteration: Replace map.keySet() with map.tailMap(prefix, true).keySet() so the scan starts at the first key that could match the prefix rather than at the beginning of the map.
• Early-exit break: Stop iterating as soon as a key no longer matches the prefix (case-insensitive regionMatches check), avoiding traversal of unrelated keys.

// Before
for (String key : map.keySet()) {
    if (key.length() > prefix.length() && key.regionMatches(true, 0, prefix, 0, prefix.length())) {
        ...
    }
}

// After
for (String key : map.tailMap(prefix, true).keySet()) {
    if (!key.regionMatches(true, 0, prefix, 0, prefix.length())) {
        break;
    }
    if (key.length() > prefix.length()) {
        ...
    }
}

Because the TreeMap uses String.CASE_INSENSITIVE_ORDER, tailMap uses the same comparator — all case variants of a given prefix are grouped consecutively, so the break is safe and no matches are skipped.

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[Copilot]

Just as a heads up, I was blocked by some firewall rules while working on your feedback. Expand below for details.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• checkstyle.org
  • Triggering command: /opt/hostedtoolcache/CodeQL/2.24.3/x64/codeql/tools/linux64/java/bin/java /opt/hostedtoolcache/CodeQL/2.24.3/x64/codeql/tools/linux64/java/bin/java -jar /opt/hostedtoolcache/CodeQL/2.24.3/x64/codeql/xml/tools/xml-extractor.jar --fileList=/tmp/codeql-scratch-3f672d5de33c41b7/dbs/java/working/files-to-index2041057654805951792.list --sourceArchiveDir=/tmp/codeql-scratch-3f672d5de33c41b7/dbs/java/src --outputDir=/tmp/codeql-scratch-3f672d5de33c41b7/dbs/java/trap/java (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)