Improve server-side error when serializing wildcard types (#8862)

1 files changed, 6 insertions, 0 deletions

diff --git a/src/com/vaadin/terminal/gwt/server/JsonCodec.java b/src/com/vaadin/terminal/gwt/server/JsonCodec.java
index 8091a1d205..df596dba45 100644
--- a/src/com/vaadin/terminal/gwt/server/JsonCodec.java
+++ b/src/com/vaadin/terminal/gwt/server/JsonCodec.java
@@ -14,6 +14,7 @@ import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.lang.reflect.ParameterizedType;
 import java.lang.reflect.Type;
+import java.lang.reflect.WildcardType;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
@@ -522,6 +523,11 @@ public class JsonCodec implements Serializable {
             throw new IllegalArgumentException("type must be defined");
         }
 
+        if (valueType instanceof WildcardType) {
+            throw new IllegalStateException(
+                    "Can not serialize type with wildcard: " + valueType);
+        }
+
         if (null == value) {
             return encodeNull();
         }