Memory
Reading a GC Log Line by Line
One run, one quantity, three answers. The allocation rate everyone derives from the default GC log is ten per cent low, and the log says why if you ask it correctly.
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Articles
Long-form writing on the JVM, its runtimes, and the frameworks built on them.
Runtime
Streams Versus Loops: What the JIT Sees
The same pipeline cost 7.05 times the loop over eight elements and 1.31 times over a million. The ratio everyone quotes is a measurement at a trip count.
Runtime
The Cost of Optional
Identical source, five call sites, one JDK 26 run - nothing allocated at the first and twelve bytes at three others. The wrapper is not what decides.
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.
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.
Runtime
How the JVM Finds and Loads a Class
A hello-world program loads 423 classes before it prints anything. Where they come from, what the JVM does to each one, and how to see 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.
Memory
G1 versus ZGC: What the Pause Numbers Hide
Sub-millisecond pauses are real, and they are not the whole cost. What the two collectors actually trade, and which numbers to compare instead.
Runtime
Escape Analysis and the Allocation That Never Happened
C2 can delete an object entirely by proving it never escapes. Here is when that works, when it silently stops, and how to measure the difference.