remove unused and not very elegant code

src/main/java/de/joshavg/simpledic/Instantiator.java

@@ -30,8 +30,4 @@ class Instantiator<T> {
         return constructor.newInstance(parameters);
     }
 
-    T createSingleton() {
-        return null;
-    }
-
 }

src/main/java/de/joshavg/simpledic/IntegrityCheck.java

@@ -121,9 +121,7 @@ class IntegrityCheck {
     }
 
     private void checkCycles() {
-        definitions.forEach(def -> {
-            checkConstructorParameter(null, def.getClz());
-        });
+        definitions.forEach(def -> checkConstructorParameter(def.getClz(), null));
     }
 
     private void checkConstructorParameter(Class<?> rootClz, Class<?> paramClz) {
@@ -131,13 +129,16 @@ class IntegrityCheck {
             throw new DependencyCycleDetected(rootClz);
         }
 
-        Class<?>[] parameterTypes = findDefinition(paramClz).getConstructor().getParameterTypes();
-        for (Class<?> innerParamClz : parameterTypes) {
-            if (rootClz == null) {
-                checkConstructorParameter(paramClz, innerParamClz);
+        ServiceDefinition def;
+        if (paramClz == null) {
+            def = findDefinition(rootClz);
         } else {
-                checkConstructorParameter(rootClz, innerParamClz);
+            def = findDefinition(paramClz);
         }
+
+        Class<?>[] parameterTypes = def.getConstructor().getParameterTypes();
+        for (Class<?> innerParamClz : parameterTypes) {
+            checkConstructorParameter(rootClz, innerParamClz);
         }
     }