diff --git a/src/de/inetsoftware/jwebassembly/module/TypeManager.java b/src/de/inetsoftware/jwebassembly/module/TypeManager.java
index 6c8e6a8..d82ed3e 100644
--- a/src/de/inetsoftware/jwebassembly/module/TypeManager.java
+++ b/src/de/inetsoftware/jwebassembly/module/TypeManager.java
@@ -803,6 +803,15 @@ public class TypeManager {
             return classIndex;
         }
 
+        /**
+         * The running index of the component/array class/type for class meta data, instanceof and interface calls.
+         * 
+         * @return the unique index or -1 id not an array
+         */
+        protected int getComponentClassIndex() {
+            return -1;
+        }
+
         /**
          * Get the fields of this struct
          * @return the fields
@@ -885,7 +894,7 @@ public class TypeManager {
             header.writeInt32( classNameIdx ); // string id of the className
 
             // header position TYPE_DESCRIPTION_ARRAY_TYPE
-            header.writeInt32( -1 );
+            header.writeInt32( getComponentClassIndex() );
 
             data.writeTo( dataStream );
         }
diff --git a/src/de/inetsoftware/jwebassembly/wasm/ArrayType.java b/src/de/inetsoftware/jwebassembly/wasm/ArrayType.java
index 1323461..6c70950 100644
--- a/src/de/inetsoftware/jwebassembly/wasm/ArrayType.java
+++ b/src/de/inetsoftware/jwebassembly/wasm/ArrayType.java
@@ -27,6 +27,8 @@ public class ArrayType extends StructType {
 
     private AnyType arrayType;
 
+    private int componentClassIndex;
+
     /**
      * Create a new array type
      * 
@@ -41,6 +43,7 @@ public class ArrayType extends StructType {
         //TODO name
         super( "[", classIndex );
         this.arrayType = arrayType;
+        this.componentClassIndex = componentClassIndex;
     }
 
     /**
@@ -51,6 +54,14 @@ public class ArrayType extends StructType {
         return arrayType;
     }
 
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    protected int getComponentClassIndex() {
+        return componentClassIndex;
+    }
+
     /**
      * {@inheritDoc}
      */