diff --git a/object.go b/object.go
index a72b79e..5757e56 100644
--- a/object.go
+++ b/object.go
@@ -442,7 +442,7 @@
 			}
 
 		default:
-			return nil, perrors.Errorf("unknown struct member type: %v", kind)
+			return nil, perrors.Errorf("unknown struct member type: %v %v", kind, typ.Name()+"."+typ.Field(index).Name)
 		}
 	} // end for
 
diff --git a/pojo.go b/pojo.go
index 0ea9c4b..de9dc16 100644
--- a/pojo.go
+++ b/pojo.go
@@ -296,7 +296,10 @@
 		return nil, cls, perrors.Errorf("illegal class index @idx %d", idx)
 	}
 	cls = pojoRegistry.classInfoList[idx]
-	clsName = pojoRegistry.j2g[cls.javaName]
+	clsName, ok = pojoRegistry.j2g[cls.javaName]
+	if !ok {
+		return nil, cls, perrors.Errorf("can not find java type name %s in registry", cls.javaName)
+	}
 	s, ok = pojoRegistry.registry[clsName]
 	if !ok {
 		return nil, cls, perrors.Errorf("can not find go type name %s in registry", clsName)