Optimize Java and JVM Applications

Java applications running on the JVM have unique performance characteristics driven by garbage collection, JIT compilation, and memory management. Proper tuning can reduce latency by 50% and memory usage by 30%. This guide covers JVM flags, garbage collector selection, heap sizing, and Spring Boot-specific optimizations for VPS deployments.

Choosing the Right Garbage Collector

Java 21+ offers several garbage collectors, each suited to different workloads:

G1GC (Default since Java 9)

# Good general-purpose choice for heaps 4-16GB
java -XX:+UseG1GC \
     -XX:MaxGCPauseMillis=200 \
     -XX:G1HeapRegionSize=16m \
     -jar app.jar

ZGC (Recommended for Low-Latency)

# Sub-millisecond pauses, ideal for web applications
# Production-ready since Java 17, generational since Java 21
java -XX:+UseZGC \
     -XX:+ZGenerational \
     -jar app.jar

# ZGC handles heaps from 256MB to 16TB with consistent