add error handle: ElementContainer

src/main/java/component/MutableDangerousField.java

@@ -57,7 +57,7 @@ public class MutableDangerousField implements TlvComponentBase, IEncodingAble {
      */
     public Block getBlockByType(VlInt tlvType) throws ComponentException {
         try {
-            return this.blocks.getElement(tlvType);
+            return this.blocks.getBlockByType(tlvType);
         } catch (BlockException e) {
             throw new ComponentException("MutableDangerousField.getBlockByType: "+e.getMessage());
         }