The ModuleReader implementation for modules in the run-time image are performance critical for the built-in class loaders. The refactoring in JDK-8360037 to use ImageReader.findNode appears to introduced a second lookup when the resource (/modules/$MODULE/$RESOURCE) is not found. This needs to be investigated and may require adding a new ImageReader API to allow usages in java.bas attempt to locate a resource with a single lookup.