presto-main/src/main/java/io/prestosql/sql/gen/Bootstrap.java/Bootstrap/bootstrap
class Bootstrap:    public static CallSite bootstrap(MethodHandles.Lookup callerLookup, String name, MethodType type, long bindingId)
    {
        ClassLoader classLoader = callerLookup.lookupClass().getClassLoader();
        checkArgument(classLoader instanceof DynamicClassLoader, "Expected %s's classloader to be of type %s", callerLookup.lookupClass().getName(), DynamicClassLoader.class.getName());

        DynamicClassLoader dynamicClassLoader = (DynamicClassLoader) classLoader;
        MethodHandle target = dynamicClassLoader.getCallSiteBindings().get(bindingId);
        checkArgument(target != null, "Binding %s for function %s%s not found", bindingId, name, type.parameterList());

        return new ConstantCallSite(target);
    }