Practical utilities
The article reviews the JVM series finale, explaining how GraalVM Native Image, Project Loom, Project Valhalla, and Project Panama each address Java’s historic shortcomings—startup latency, heavyweight threads, object overhead, and clumsy native interop—while weighing their trade‑offs and future impact.
This article explains the three fundamental problems of Java concurrency—visibility, atomicity, and ordering—describes how the Java Memory Model and happens‑before rules address them, and details the low‑level implementations and optimizations of volatile, synchronized, lock upgrading, and the removal of biased locking in JDK 15‑17.
This article explains why the JVM combines interpretation and Just‑In‑Time compilation, how it detects hot code with invocation and back‑edge counters, the tiered C1/C2 compilation process, key JIT optimizations like method inlining, and how to observe JIT activity using JVM flags.
This article guides backend engineers through practical JVM garbage‑collection tuning and on‑line incident diagnosis, covering measurement‑first principles, JDK 8 vs 17 log changes, key JVM flags, essential tooling, and step‑by‑step real‑world cases for CPU spikes, memory leaks, and deadlocks.
This article walks through the evolution of Java garbage collectors—from the early Serial collector to modern low‑latency ZGC and Shenandoah—explaining how throughput, pause time, and safepoints shape each collector’s design and what changes matter when upgrading from JDK 8 to JDK 17.
This article explains the three fundamental garbage‑collection algorithms (Mark‑Sweep, Copying, Mark‑Compact), the three generational hypotheses, the structure and rules of the young generation, the distinctions among Minor, Major and Full GCs, and how remembered sets and card tables efficiently handle cross‑generation references in the JVM.
This article walks through the JVM's six-step process for creating a new object, explains heap allocation strategies and thread‑local buffers, details escape analysis optimizations, reveals the exact memory layout of an object including header and padding, compares handle versus direct pointer access, and describes reachability‑based garbage collection with the four Java reference types.
This article walks through how the Java compiler (javac) transforms source code into bytecode, revealing the hidden steps of syntactic‑sugar removal, generic type erasure, autoboxing pitfalls, foreach/varargs handling, the five invoke instructions, static versus dynamic method dispatch, and why Lambda expressions rely on invokedynamic rather than anonymous inner classes.
This article walks through the five JVM runtime data areas, explains the distinction between the JVM specification and HotSpot implementation, compares the PermGen to Metaspace transition from JDK 8 to JDK 17, and provides hands‑on code to reproduce each type of memory‑related OutOfMemoryError.
The article explains the difference between character sets and encodings, shows that MySQL’s utf8 is actually an alias for utf8mb3, demonstrates how using the wrong charset or collation causes garbled data, and provides practical steps to consistently use utf8mb4 across versions and connections.
