diff --git a/moshi/src/main/java/com/squareup/moshi/ClassJsonAdapter.java b/moshi/src/main/java/com/squareup/moshi/ClassJsonAdapter.java
index 500b293..a149116 100644
--- a/moshi/src/main/java/com/squareup/moshi/ClassJsonAdapter.java
+++ b/moshi/src/main/java/com/squareup/moshi/ClassJsonAdapter.java
@@ -79,18 +79,11 @@ final class ClassJsonAdapter<T> extends JsonAdapter<T> {
       if (Modifier.isAbstract(rawType.getModifiers())) {
         throw new IllegalArgumentException("Cannot serialize abstract class " + rawType.getName());
       }
-      try {
-        //noinspection unchecked if the Class.forName works, the cast will work.
-        Class<? extends Annotation> metadataClass =
-            (Class<? extends Annotation>) Class.forName("kotlin.Metadata");
-        if (rawType.isAnnotationPresent(metadataClass)) {
-          throw new IllegalArgumentException("Cannot serialize Kotlin type " + rawType.getName()
-              + ". Reflective serialization of Kotlin classes without using kotlin-reflect has "
-              + "undefined and unexpected behavior. Please use KotlinJsonAdapter from the "
-              + "moshi-kotlin artifact or use code gen from the moshi-kotlin-codegen artifact.");
-        }
-      } catch (ClassNotFoundException ignored) {
-
+      if (Util.isKotlin(rawType)) {
+        throw new IllegalArgumentException("Cannot serialize Kotlin type " + rawType.getName()
+            + ". Reflective serialization of Kotlin classes without using kotlin-reflect has "
+            + "undefined and unexpected behavior. Please use KotlinJsonAdapter from the "
+            + "moshi-kotlin artifact or use code gen from the moshi-kotlin-codegen artifact.");
       }
 
       ClassFactory<Object> classFactory = ClassFactory.get(rawType);
diff --git a/moshi/src/main/java/com/squareup/moshi/internal/Util.java b/moshi/src/main/java/com/squareup/moshi/internal/Util.java
index 2480744..babd6e9 100644
--- a/moshi/src/main/java/com/squareup/moshi/internal/Util.java
+++ b/moshi/src/main/java/com/squareup/moshi/internal/Util.java
@@ -35,7 +35,6 @@ import java.lang.reflect.WildcardType;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
-import java.util.HashSet;
 import java.util.LinkedHashSet;
 import java.util.NoSuchElementException;
 import java.util.Set;
@@ -49,15 +48,18 @@ public final class Util {
   public static final Set<Annotation> NO_ANNOTATIONS = Collections.emptySet();
   public static final Type[] EMPTY_TYPE_ARRAY = new Type[] {};
   @Nullable private static final Class<?> DEFAULT_CONSTRUCTOR_MARKER;
+  @Nullable private static final Class<? extends Annotation> METADATA;
 
   static {
-    Class<?> clazz;
+    Class<? extends Annotation> metadata = null;
+    Class<?> defaultConstructorMarker = null;
     try {
-      clazz = Class.forName("kotlin.jvm.internal.DefaultConstructorMarker");
-    } catch (ClassNotFoundException e) {
-      clazz = null;
+      metadata = (Class<? extends Annotation>) Class.forName("kotlin.Metadata");
+      defaultConstructorMarker = Class.forName("kotlin.jvm.internal.DefaultConstructorMarker");
+    } catch (ClassNotFoundException ignored) {
     }
-    DEFAULT_CONSTRUCTOR_MARKER = clazz;
+    METADATA = metadata;
+    DEFAULT_CONSTRUCTOR_MARKER = defaultConstructorMarker;
   }
 
   private Util() {
@@ -171,7 +173,7 @@ public final class Util {
   }
 
   public static Type resolve(Type context, Class<?> contextRawType, Type toResolve) {
-    return resolve(context, contextRawType, toResolve, new HashSet<TypeVariable>());
+    return resolve(context, contextRawType, toResolve, new LinkedHashSet<TypeVariable>());
   }
 
   private static Type resolve(Type context, Class<?> contextRawType, Type toResolve,
@@ -553,6 +555,10 @@ public final class Util {
     }
   }
 
+  public static boolean isKotlin(Class<?> targetClass) {
+    return METADATA != null && targetClass.isAnnotationPresent(METADATA);
+  }
+
   /**
    * Reflectively looks up the defaults constructor of a kotlin class.
    *