We have observed a performance regression (~9–10 seconds delay) during the Spring context refresh phase after upgrading our application from Spring 6.1.21 to Spring 6.2.11. There are over 50K beans in the ApplicationContext.
Steps to Reproduce:
- Start application using Spring 6.1.21 – observe normal startup time.
- Change only the Spring version to 6.2.11 – observe ~9–10 seconds delay during the refresh phase.
- The issue is consistently reproducible by switching between these two versions.
Environment:
- Spring Framework: 6.1.21 (baseline) vs. 6.2.11 (regression)
- Local benchmark using JMH (see Results section below)
- No other code changes between versions
Observed Behavior (Spring 6.2):
Multiple thread dumps taken during the refresh phase show the main thread consistently stuck in: - PlaceholderConfigurerSupport.doProcessProperties - PropertyPlaceholderHelper - PlaceholderParser
Expected Behavior (Spring 6.1):
- Startup completes without delay.
- Thread traces show smooth initialization and no significant time spent in property placeholder resolution.
Analysis:
- The extended time in Spring 6.2 appears related to property placeholder resolution becoming a performance bottleneck.
- This behavior was not present in 6.1 and is isolated to property processing logic during context initialization.
- See the following from Spring 6.2 release notes:
The parser for property placeholders has been completely rewritten to be as lenient as possible. As a result, certain constructs that previously worked by accident rather than by design are no longer possible.
Benchmark Setup:
Created a local benchmark repo using JMH to isolate the issue and confirm the regression.
Results:
=== Spring 6.1 Results ===
Benchmark (propertyCount) Mode Cnt Score Error Units
SpringPropertyResolutionBenchmark.benchmarkBatchPropertyResolution 10000 avgt 15 5.371 ± 0.124 us/op
SpringPropertyResolutionBenchmark.benchmarkComplexPropertyResolution 10000 avgt 15 13.733 ± 0.138 us/op
SpringPropertyResolutionBenchmark.benchmarkNestedPropertyResolution 10000 avgt 15 11.659 ± 0.123 us/op
SpringPropertyResolutionBenchmark.benchmarkPropertyPlaceholderHelper 10000 avgt 15 11.875 ± 0.152 us/op
SpringPropertyResolutionBenchmark.benchmarkSimplePropertyResolution 10000 avgt 15 5.074 ± 0.103 us/op
=== Spring 6.2 Results ===
Benchmark (propertyCount) Mode Cnt Score Error Units
SpringPropertyResolutionBenchmark.benchmarkBatchPropertyResolution 10000 avgt 15 8.391 ± 0.171 us/op
SpringPropertyResolutionBenchmark.benchmarkComplexPropertyResolution 10000 avgt 15 26.490 ± 0.730 us/op
SpringPropertyResolutionBenchmark.benchmarkNestedPropertyResolution 10000 avgt 15 20.151 ± 0.315 us/op
SpringPropertyResolutionBenchmark.benchmarkPropertyPlaceholderHelper 10000 avgt 15 23.800 ± 0.412 us/op
SpringPropertyResolutionBenchmark.benchmarkSimplePropertyResolution 10000 avgt 15 8.015 ± 0.078 us/op