Default analyzer deserialization to custom type when unspecified

CHANGELOG.md

@@ -42,6 +42,7 @@ This section is for maintaining a changelog for all breaking changes for the cli
 ### Removed
 
 ### Fixed
+- Fixed error when deserializing an analyzer without `type` specified ([#1033](https://github.com/opensearch-project/opensearch-java/pull/1033))
 
 ### Security
 

java-client/src/main/java/org/opensearch/client/opensearch/_types/analysis/Analyzer.java

@@ -606,7 +606,7 @@ protected static void setupAnalyzerDeserializer(ObjectDeserializer<Builder> op)
         op.add(Builder::smartcn, SmartcnAnalyzer._DESERIALIZER, Kind.Smartcn.jsonValue());
         op.add(Builder::cjk, CjkAnalyzer._DESERIALIZER, Kind.Cjk.jsonValue());
 
-        op.setTypeProperty("type", null);
+        op.setTypeProperty("type", Kind.Custom.jsonValue());
 
     }
 

java-client/src/test/java/org/opensearch/client/opensearch/_types/analysis/AnalyzerDeserializerTest.java

@@ -0,0 +1,30 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.client.opensearch._types.analysis;
+
+import org.junit.Test;
+import org.opensearch.client.opensearch.model.ModelTestCase;
+
+public class AnalyzerDeserializerTest extends ModelTestCase {
+    @Test
+    public void deserializesTypelessCustomAnalyzer() {
+        String json = "{\n"
+            + "    \"filter\": [\"kuromoji_baseform\", \"ja_stop\"],\n"
+            + "    \"char_filter\": [\"icu_normalizer\"],\n"
+            + "    \"tokenizer\": \"kuromoji_tokenizer\"\n"
+            + "}";
+
+        Analyzer analyzer = fromJson(json, Analyzer._DESERIALIZER);
+        assertTrue(analyzer.isCustom());
+        assertEquals("kuromoji_tokenizer", analyzer.custom().tokenizer());
+        assertEquals("icu_normalizer", analyzer.custom().charFilter().get(0));
+        assertEquals("kuromoji_baseform", analyzer.custom().filter().get(0));
+        assertEquals("ja_stop", analyzer.custom().filter().get(1));
+    }
+}