public Lookup getExtensionLookup() {
Lookup lookup = extensionLookupRef.get();
if (lookup == null) {
lookup = Lookups.fixed(new JavaExtensionNodes(this),
new JavaProjectContextActions(this),
new GradleJavaBuiltInCommands(this),
new JavaInitScriptQuery());
if (extensionLookupRef.compareAndSet(null, lookup)) {
initLookup(lookup);
}