[jOOQ/jOOQ#7076] ForcedType enum with no matching value being converted

to last enum value

jOOQ/src/main/java/org/jooq/impl/EnumConverter.java

@@ -75,13 +75,20 @@ public /* non-final */ class EnumConverter<T, U extends Enum<U>> extends Abstrac
         this.to = to;
         this.lookup = new LinkedHashMap<>();
 
-        for (U u : toType.getEnumConstants())
-            this.lookup.put(to(u), u);
+        for (U u : toType.getEnumConstants()) {
+            T key = to(u);
+
+            if (key != null)
+                this.lookup.put(key, u);
+        }
     }
 
     @Override
     public final U from(T t) {
-        return lookup.get(t);
+        if (t == null)
+            return null;
+        else
+            return lookup.get(t);
     }
 
     /**