Detecting concurrency issues with JCStress

Java is a very popular programming language with a consistent set of multithreading & multiprocessing features to solve all kind of modern Enterprise problems and Threads share memory as part of the Java concurrency Model.

Developers use popular frameworks like Spring, Quarkus, Micronaut, Akka or Spark every day but in some scenarios, it is necessary to use concurrency, but it is a reality that learning curve is not easy and sometimes, software deployed on cloud includes some hidden concurrency bugs.

The talk will review root causes for Concurrency issues, and it will do an introduction about the Java tool JCStress explaining how to create tests for those Java class which share state.

• https://www.meetup.com/nl-NL/amsterdam-java-user-group/events/287658432/

Running the example in local:

sdk env
./gradlew clean build jcstress
./gradlew clean jcstress --tests "Calculator4Test"
./gradlew clean build
./gradlew clean bootRun

http://localhost:8080/swagger-ui/index.html
http://localhost:8080/v3/api-docs
https://editor.swagger.io/

Running Visualvm, Jmeter & Taurus to add load:

sdk install visualvm
visualvm --jdkhome  $JAVA_HOME

java -Xms256m -Xmx256m -XX:+UseParallelGC -jar build/libs/101-concurrency-0.1.0-SNAPSHOT.jar
sdk install jmeter
jmeter -t jmeterConf.jmx
jmeter -t jmeterConf.jmx -n
jmeter -t jmeterConf2.jmx

brew install python
python3 --version
pip3 install bzt
bzt taurusConf.yaml

sdk env
jwebserver -p 8000 -d  $PWD/docs

• https://docs.oracle.com/javase/specs/jls/se8/html/jls-17.html
• https://download.oracle.com/otndocs/jcp/memory_model-1.0-pfd-spec-oth-JSpec/
• https://gee.cs.oswego.edu/dl/jmm/cookbook.html
• https://github.com/openjdk/jcstress
• https://github.com/reyerizo/jcstress-gradle-plugin