3 posts tagged with "jvm"

Calling Thread.start() asks the JVM to create a new execution thread. Calling run() directly does not create a thread; it executes on the current caller.

The Java Virtual Machine provides a managed execution environment for bytecode. Understanding its memory model, class lifecycle, execution engine, and diagnostics makes Java failures easier to explain and tune.

This note explains a typical Java startup command used while running load tests on Linux:

java -server \
  -XX:+HeapDumpOnOutOfMemoryError \
  -Xms512m \
  -Xmx512m \
  -XX:+UseG1GC \
  -XX:MaxGCPauseMillis=250 \
  -XX:G1ReservePercent=20 \
  -Djava.security.egd=file:/dev/urandom \
  -jar xxxx.jar

JVM options must appear before -jar or the main class. Application arguments belong after the JAR name or main class. When diagnosing startup problems, record the exact command, Java version, environment variables, operating-system limits, and container memory limits.