diff --git a/async-query-core/src/main/java/org/opensearch/sql/spark/parameter/DataSourceSparkParameterComposer.java b/async-query-core/src/main/java/org/opensearch/sql/spark/parameter/DataSourceSparkParameterComposer.java
index 4411bfe22d..324889b6e0 100644
--- a/async-query-core/src/main/java/org/opensearch/sql/spark/parameter/DataSourceSparkParameterComposer.java
+++ b/async-query-core/src/main/java/org/opensearch/sql/spark/parameter/DataSourceSparkParameterComposer.java
@@ -9,7 +9,12 @@
 import org.opensearch.sql.spark.asyncquery.model.AsyncQueryRequestContext;
 import org.opensearch.sql.spark.dispatcher.model.DispatchQueryRequest;
 
-/** Compose Spark parameter based on DataSourceMetadata */
+/**
+ * Compose Spark parameters specific to the {@link
+ * org.opensearch.sql.datasource.model.DataSourceType} based on the {@link DataSourceMetadata}. For
+ * the parameters not specific to {@link org.opensearch.sql.datasource.model.DataSourceType}, please
+ * use {@link GeneralSparkParameterComposer}.
+ */
 public interface DataSourceSparkParameterComposer {
   void compose(
       DataSourceMetadata dataSourceMetadata,
diff --git a/async-query-core/src/main/java/org/opensearch/sql/spark/parameter/GeneralSparkParameterComposer.java b/async-query-core/src/main/java/org/opensearch/sql/spark/parameter/GeneralSparkParameterComposer.java
index b5200d550c..c3d46ba5c6 100644
--- a/async-query-core/src/main/java/org/opensearch/sql/spark/parameter/GeneralSparkParameterComposer.java
+++ b/async-query-core/src/main/java/org/opensearch/sql/spark/parameter/GeneralSparkParameterComposer.java
@@ -8,8 +8,22 @@
 import org.opensearch.sql.spark.asyncquery.model.AsyncQueryRequestContext;
 import org.opensearch.sql.spark.dispatcher.model.DispatchQueryRequest;
 
-/** Compose spark submit parameters. See {@link SparkParameterComposerCollection}. */
+/**
+ * Compose spark submit parameters based on the request and context. For {@link
+ * org.opensearch.sql.datasource.model.DataSourceType} specific parameters, please use {@link
+ * DataSourceSparkParameterComposer}. See {@link SparkParameterComposerCollection}.
+ */
 public interface GeneralSparkParameterComposer {
+
+  /**
+   * Modify sparkSubmitParameters based on dispatchQueryRequest and context.
+   *
+   * @param sparkSubmitParameters Implementation of this method will modify this.
+   * @param dispatchQueryRequest Request. Implementation can refer it to compose
+   *     sparkSubmitParameters.
+   * @param context Context of the request. Implementation can refer it to compose
+   *     sparkSubmitParameters.
+   */
   void compose(
       SparkSubmitParameters sparkSubmitParameters,
       DispatchQueryRequest dispatchQueryRequest,
diff --git a/async-query-core/src/main/java/org/opensearch/sql/spark/parameter/SparkParameterComposerCollection.java b/async-query-core/src/main/java/org/opensearch/sql/spark/parameter/SparkParameterComposerCollection.java
index 281759afd2..a6a88738bf 100644
--- a/async-query-core/src/main/java/org/opensearch/sql/spark/parameter/SparkParameterComposerCollection.java
+++ b/async-query-core/src/main/java/org/opensearch/sql/spark/parameter/SparkParameterComposerCollection.java
@@ -16,12 +16,19 @@
 import org.opensearch.sql.spark.asyncquery.model.AsyncQueryRequestContext;
 import org.opensearch.sql.spark.dispatcher.model.DispatchQueryRequest;
 
-/** Stores Spark parameter composers and dispatch compose request to each composer */
+/**
+ * Stores Spark parameter composers and dispatch compose request to each composer. Composers should
+ * be registered during initialization such as in Guice Module.
+ */
 public class SparkParameterComposerCollection {
-  Collection<GeneralSparkParameterComposer> generalComposers = new ArrayList<>();
-  Map<DataSourceType, Collection<DataSourceSparkParameterComposer>> datasourceComposers =
+  private Collection<GeneralSparkParameterComposer> generalComposers = new ArrayList<>();
+  private Map<DataSourceType, Collection<DataSourceSparkParameterComposer>> datasourceComposers =
       new HashMap<>();
 
+  /**
+   * Register composers for specific DataSourceType. The registered composer is called only if the
+   * request is for the dataSourceType.
+   */
   public void register(DataSourceType dataSourceType, DataSourceSparkParameterComposer composer) {
     if (!datasourceComposers.containsKey(dataSourceType)) {
       datasourceComposers.put(dataSourceType, new LinkedList<>());
@@ -29,6 +36,10 @@ public void register(DataSourceType dataSourceType, DataSourceSparkParameterComp
     datasourceComposers.get(dataSourceType).add(composer);
   }
 
+  /**
+   * Register general composer. The composer is called when spark parameter is generated regardless
+   * of datasource type.
+   */
   public void register(GeneralSparkParameterComposer composer) {
     generalComposers.add(composer);
   }
diff --git a/async-query/src/main/java/org/opensearch/sql/spark/config/SparkExecutionEngineConfigClusterSettingLoader.java b/async-query/src/main/java/org/opensearch/sql/spark/config/SparkExecutionEngineConfigClusterSettingLoader.java
index 561a4653a5..73b057ca5c 100644
--- a/async-query/src/main/java/org/opensearch/sql/spark/config/SparkExecutionEngineConfigClusterSettingLoader.java
+++ b/async-query/src/main/java/org/opensearch/sql/spark/config/SparkExecutionEngineConfigClusterSettingLoader.java
@@ -14,6 +14,7 @@
 import org.apache.commons.lang3.StringUtils;
 import org.opensearch.sql.common.setting.Settings;
 
+/** Load SparkExecutionEngineConfigClusterSetting from settings with privilege check. */
 @RequiredArgsConstructor
 public class SparkExecutionEngineConfigClusterSettingLoader {
   private final Settings settings;