How to enable the JDT debug and builder flags?

[safisa]

Hi,

I have some issues with my project auto-build, and I checked the code in the eclipse.jdt.core project and found the build logic is in the file: org.eclipse.jdt.core/model/org/eclipse/jdt/internal/core/builder/JavaBuilder.java.
I saw that it adds many logs/trace info about the build process and why it happens, but all are only when using those flags:

org.eclipse.jdt.core/debug=true
org.eclipse.jdt.core/debug/builder=true

How and where can I set those flags?

Thanks