From 24511a6721681734b31ea7ad8d851f58ea112dbf Mon Sep 17 00:00:00 2001
From: kkonrad <kkonrad@mail.com>
Date: Tue, 25 Aug 2020 00:13:00 +0200
Subject: [PATCH] FIX: potential duplicate log entry due to race condition

---
 src/main/java/com/networknt/schema/JsonMetaSchema.java | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/main/java/com/networknt/schema/JsonMetaSchema.java b/src/main/java/com/networknt/schema/JsonMetaSchema.java
index 3cbffc90c..77fb790c2 100644
--- a/src/main/java/com/networknt/schema/JsonMetaSchema.java
+++ b/src/main/java/com/networknt/schema/JsonMetaSchema.java
@@ -333,8 +333,7 @@ public JsonValidator newValidator(ValidationContext validationContext, String sc
         try {
             Keyword kw = keywords.get(keyword);
             if (kw == null) {
-                if (!UNKNOWN_KEYWORDS.containsKey(keyword)) {
-                    UNKNOWN_KEYWORDS.put(keyword, keyword);
+                if (UNKNOWN_KEYWORDS.put(keyword, keyword) == null) {
                     logger.warn("Unknown keyword " + keyword + " - you should define your own Meta Schema. If the keyword is irrelevant for validation, just use a NonValidationKeyword");
                 }
                 return null;