package org.pojomatic.internal;
   
   public class ClassDefinerFactory {
     private static volatile ClassDefiner CLASS_DEFINER;
     private final static Object MUTEX = new Object();
   
     // Avoid initializing when the class is first loaded, so that any exceptions don't get masked as NoClassDefFoundErrors
     public static ClassDefiner getDefiner() {
       if (CLASS_DEFINER == null) {
        synchronized (MUTEX) {
          if (CLASS_DEFINER == null) {
            CLASS_DEFINER = makeDefiner();
          }
        }
      }
      return CLASS_DEFINER;
    }
  
    private static ClassDefiner makeDefiner() {
      try {
        return (ClassDefiner) ClassDefiner.class.getClassLoader().loadClass("org.pojomatic.internal.LookupClassDefiner")
          .getConstructor()
          .newInstance();
      } catch (ReflectiveOperationException | UnsupportedClassVersionError e) {
        return new ClassLoaderClassDefiner();
      }
    }
  }