Java String Concatenation Performance: + vs StringBuilder
Java string concatenation performance on JDK 25 with JMH results, how + compiles since JEP 280, why += in loops is slow, and concat() vs StringBuilder.
JMH Java Microbenchmark Harness: Setup, Blackhole, Pitfalls
Learn the JMH Java Microbenchmark Harness with the Maven archetype, the Java 23+ processor fix, @State, @Param, Blackhole, real results and pitfalls.
JMeter Tutorial for Beginners: Load Test a REST API
Learn JMeter 5.6.3 step by step: build a test plan with a thread group, HTTP requests, an assertion and think time, run it in CLI mode and read the HTML report.
Spring Boot DevTools: Automatic Restart and Development Settings
Set up Spring Boot DevTools, observe a classpath restart after compilation, and distinguish static-resource changes from a packaged JAR run. Verified with Spring Boot 4.1.2.
How to Improve Java Application Performance
Improve Java performance with a measurable goal, realistic baseline and focused investigation. Find bottlenecks and compare changes without guessing.
Iterate HashMap in Java: Fastest Way With JMH Results
Learn to iterate HashMap in Java with entrySet, forEach, keySet and streams, remove entries safely, and compare each way with JMH results on JDK 25.