diff --git a/java-client/src/test/java/org/opensearch/client/opensearch/_types/analysis/PatternReplaceCharFilterTest.java b/java-client/src/test/java/org/opensearch/client/opensearch/_types/analysis/PatternReplaceCharFilterTest.java
index 46bbdce85b..7a7d15f93a 100644
--- a/java-client/src/test/java/org/opensearch/client/opensearch/_types/analysis/PatternReplaceCharFilterTest.java
+++ b/java-client/src/test/java/org/opensearch/client/opensearch/_types/analysis/PatternReplaceCharFilterTest.java
@@ -43,7 +43,7 @@ public void testCreatePatternReplaceCharFilterWithFlags() {
     }
 
     @Test
-    public void testDeserializePatternReplaceCharFilter() {
+    public void testDeserializePatternReplaceCharFilterWithAllFields() {
         String jsonString =
             "{\"type\": \"pattern_replace\", \"pattern\": \"pattern\", \"replacement\": \"replacement\", \"flags\": \"flags\"}";
 
@@ -56,4 +56,16 @@ public void testDeserializePatternReplaceCharFilter() {
         assertEquals("replacement", patternReplaceCharFilter.replacement());
         assertEquals("flags", patternReplaceCharFilter.flags());
     }
+
+    @Test
+    public void testDeserializePatternReplaceCharFilterWithPatternOnly() {
+        String jsonString = "{\"type\": \"pattern_replace\", \"pattern\": \"pattern\"}";
+
+        StringReader reader = new StringReader(jsonString);
+        JacksonJsonpMapper mapper = new JacksonJsonpMapper();
+        JsonParser parser = mapper.jsonProvider().createParser(reader);
+
+        PatternReplaceCharFilter patternReplaceCharFilter = PatternReplaceCharFilter._DESERIALIZER.deserialize(parser, mapper);
+        assertEquals("pattern", patternReplaceCharFilter.pattern());
+    }
 }