diff --git a/arclight-forge/src/main/java/io/izzel/arclight/boot/asm/EnumDefinalizer.java b/arclight-forge/src/main/java/io/izzel/arclight/boot/asm/EnumDefinalizer.java
index 6b84210a..32df9e73 100644
--- a/arclight-forge/src/main/java/io/izzel/arclight/boot/asm/EnumDefinalizer.java
+++ b/arclight-forge/src/main/java/io/izzel/arclight/boot/asm/EnumDefinalizer.java
@@ -10,7 +10,7 @@ import java.util.Set;
 
 public class EnumDefinalizer implements Implementer {
 
-    private static final Set<String> ENUM = Set.of(
+    static final Set<String> ENUM = Set.of(
         "org/bukkit/Material",
         "org/bukkit/potion/PotionType",
         "org/bukkit/entity/EntityType",
diff --git a/arclight-forge/src/main/java/io/izzel/arclight/boot/asm/InventoryImplementer.java b/arclight-forge/src/main/java/io/izzel/arclight/boot/asm/InventoryImplementer.java
index af4b3588..92d72505 100644
--- a/arclight-forge/src/main/java/io/izzel/arclight/boot/asm/InventoryImplementer.java
+++ b/arclight-forge/src/main/java/io/izzel/arclight/boot/asm/InventoryImplementer.java
@@ -57,13 +57,16 @@ public class InventoryImplementer implements Implementer {
             if (t instanceof LocalizedException) {
                 ArclightImplementer.LOGGER.error(MARKER, ((LocalizedException) t).node(), ((LocalizedException) t).args());
             } else {
-                ArclightImplementer.LOGGER.error(t);
+                ArclightImplementer.LOGGER.error(MARKER, "Error processing class", t);
             }
             return false;
         }
     }
 
     private boolean isInventoryClass(ClassNode node, ILaunchPluginService.ITransformerLoader transformerLoader) throws Throwable {
+        if (node == null) { // maybe runtime defined class
+            return false;
+        }
         Integer ret = map.get(node.name);
         if (ret != null) return ret > 1;
         Integer i = map.get(node.superName);
@@ -89,21 +92,19 @@ public class InventoryImplementer implements Implementer {
 
     private ClassNode findClass(String typeName, ILaunchPluginService.ITransformerLoader transformerLoader) throws Exception {
         try {
+            byte[] array;
             InputStream stream = Thread.currentThread().getContextClassLoader().getResourceAsStream(typeName + ".class");
-            if (stream == null) throw LocalizedException.checked("implementer.not-found", typeName);
-            byte[] array = ByteStreams.toByteArray(stream);
+            if (stream != null) {
+                array = ByteStreams.toByteArray(stream);
+            } else {
+                array = transformerLoader.buildTransformedClassNodeFor(Type.getObjectType(typeName).getClassName());
+            }
             ClassNode node = new ClassNode();
             new ClassReader(array).accept(node, ClassReader.SKIP_CODE);
             return node;
-        } catch (Throwable e) {
-            try {
-                byte[] bytes = transformerLoader.buildTransformedClassNodeFor(Type.getObjectType(typeName).getClassName());
-                ClassNode node = new ClassNode();
-                new ClassReader(bytes).accept(node, ClassReader.SKIP_CODE);
-                return node;
-            } catch (Throwable t) {
-                throw LocalizedException.checked("implementer.not-found", typeName);
-            }
+        } catch (ClassNotFoundException e) {
+            ArclightImplementer.LOGGER.debug("implementer.not-found", typeName);
+            return null;
         }
     }
 
diff --git a/arclight-forge/src/main/java/io/izzel/arclight/boot/asm/SwitchTableFixer.java b/arclight-forge/src/main/java/io/izzel/arclight/boot/asm/SwitchTableFixer.java
index ba92f86b..f5e2d518 100644
--- a/arclight-forge/src/main/java/io/izzel/arclight/boot/asm/SwitchTableFixer.java
+++ b/arclight-forge/src/main/java/io/izzel/arclight/boot/asm/SwitchTableFixer.java
@@ -1,6 +1,5 @@
 package io.izzel.arclight.boot.asm;
 
-import com.google.common.collect.ImmutableSet;
 import cpw.mods.modlauncher.serviceapi.ILaunchPluginService;
 import org.apache.logging.log4j.Marker;
 import org.apache.logging.log4j.MarkerManager;
@@ -27,13 +26,7 @@ public class SwitchTableFixer implements Implementer, Function<byte[], byte[]> {
 
     public static final SwitchTableFixer INSTANCE = new SwitchTableFixer();
     private static final Marker MARKER = MarkerManager.getMarker("SWITCH_TABLE");
-    private static final Set<String> ENUMS = ImmutableSet.<String>builder()
-        .add("org/bukkit/Material")
-        .add("org/bukkit/entity/EntityType")
-        .add("org/bukkit/World$Environment")
-        .add("org/bukkit/entity/Villager$Profession")
-        .add("org/bukkit/block/Biome")
-        .build();
+    private static final Set<String> ENUMS = EnumDefinalizer.ENUM;
 
     @Override
     public byte[] apply(byte[] bytes) {