[configuration] ConfigurationKeysLoader now caches.

src/core/lombok/core/configuration/ConfigurationKeysLoader.java

@@ -23,18 +23,23 @@ package lombok.core.configuration;
 
 import java.io.IOException;
 import java.util.Iterator;
+import java.util.concurrent.atomic.AtomicBoolean;
 
 import lombok.ConfigurationKeys;
 import lombok.core.SpiLoadUtil;
 
 public interface ConfigurationKeysLoader {
 	public class LoaderLoader {
+		private static final AtomicBoolean alreadyLoaded = new AtomicBoolean(false);
 		private LoaderLoader() {}
 		
 		public static void loadAllConfigurationKeys() {
+			if (alreadyLoaded.get()) return;
+			
 			try {
 				Class.forName(ConfigurationKeys.class.getName());
 			} catch (Throwable ignore) {}
+			
 			try {
 				Iterator<ConfigurationKeysLoader> iterator = SpiLoadUtil.findServices(ConfigurationKeysLoader.class, ConfigurationKeysLoader.class.getClassLoader()).iterator();
 				while (iterator.hasNext()) {
@@ -44,6 +49,8 @@ public interface ConfigurationKeysLoader {
 				}
 			} catch (IOException e) {
 				throw new RuntimeException("Can't load config keys; services file issue.", e);
+			} finally {
+				alreadyLoaded.set(true);
 			}
 		}
 	}