A shim refers to any piece of code that performs interception of an API call and provides a layer of abstraction.
PulseLogger:
com.sun.javafx.logging.PulseLoggercom.sun.javafx.logging.Logger
PerformanceTracker:
com.sun.javafx.perf.PerformanceTracker
OpenJDK and OpenJFX are licensed under the GNU General Public License, version 2, with the Classpath Exception.