Diagnostics
JFR: The Events You Actually Need
Sixty seconds of default settings produced 4.3 MB, three quarters of it one event type, and none of it answered whether the application was lock-contended.
Topic
profiling
Articles on “profiling”
Runtime
What a Safepoint Actually Stops
One collection, reported as 2.275 ms by the GC log and 29.6 ms by the safepoint log. The gap is time to safepoint, and each instrument hides a different part of it.
Frameworks
Where Spring Boot Startup Time Goes
Startup time is class loading, condition evaluation and JIT warmup in some proportion. Measure the split before reaching for a fix.
Diagnostics
Reading a Thread Dump Without Guessing
A thread dump answers precise questions if you ask them precisely. What each state really means, and the traps that produce confident wrong diagnoses.