Estimated time: 10 minutes.
Let’s continue to experiment on the example project we created before.
Locate the sample project we created:
cd primes-web
We have the project built and can run it with the java like this:
```shell script java -jar build/libs/primes-web-0.1-all.jar
--------------------------
There's a number of options available to turn on the additional logging about the compiler events, which you can find in the [docs](https://github.com/oracle/graal/blob/master/compiler/docs/Debugging.md).
One particular options is interesting to check if a certain piece of code you're interested in get to the JIT:
`-Dgraal.PrintCompilation=true`.
Run the application like this and we'll see a bunch of output that we can interpret:
java -Dgraal.PrintCompilation=true -jar build/libs/primes-web-0.1-all.jar
Now to inspect the actual optimizations the compiler does you can enable GraalVM to dump the compiler graphs for the code it processes.
java -Dgraal.Dump=:2 -Dgraal.MethodFilter=PrimesController.* -jar build/libs/primes-web-0.1-all.jar
This enables the dump and filters it to only contain the interesting classes in our app.
Apply the load:
hey -z 60s http://localhost:8080/primes/random/100
Check the log for the location of the files, a line like:
Dumping IGV graphs in /home/opc/primes-web/graal_dumps/2020.11.25.12.42.21.147
```
Download the .bgv files.
Run the idealgraphvizualizer locally, it’s GUI application, load the graphs into it.
Explore the transformations.
Next, we’ll try to learn about the polyglot nature of GraalVM.