UNDF: UNDF-2026-000000506

pulsar-0002: JavaInstanceRunnable — List.contains() inside config key validation loop

Defect ID

pulsar-0002

File:Line

pulsar-functions/instance/src/main/java/org/apache/pulsar/functions/instance/JavaInstanceRunnable.java:987

Description

In setupConfig():

final List<String> allFields = BeanPropertiesReader.getBeanProperties(configClass); // List<String>
for (String s : config.keySet()) {           // O(K) iterations over config keys
    if (!allFields.contains(s)) {            // O(F) linear scan over field names
        ...
    }
}

allFields is a List<String> returned by BeanPropertiesReader.getBeanProperties(). Each .contains() is O(F) where F = number of bean fields. Total: O(K × F).

While this runs at function startup (not hot per-message), it runs once per function instance initialization. For a config class with 200 fields and 150 config keys, this is 30,000 comparisons vs 350 with a HashSet.

Complexity

Slow: O(K × F) — List.contains() = O(F)
Fast: O(K) — HashSet.contains() = O(1)

Severity

MEDIUM

Speedup Estimate

~F× improvement = 200x at F=200 fields.

Fix

Convert allFields to HashSet<String> immediately after retrieval:

Set<String> allFieldsSet = new HashSet<>(BeanPropertiesReader.getBeanProperties(configClass));
for (String s : config.keySet()) {
    if (!allFieldsSet.contains(s)) { ... }
}

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