diff --git a/catalogs/catalog-jdbc-common/src/main/java/com/datastrato/gravitino/catalog/jdbc/operation/JdbcDatabaseOperations.java b/catalogs/catalog-jdbc-common/src/main/java/com/datastrato/gravitino/catalog/jdbc/operation/JdbcDatabaseOperations.java
index c47b778639a..6c0be7351c3 100644
--- a/catalogs/catalog-jdbc-common/src/main/java/com/datastrato/gravitino/catalog/jdbc/operation/JdbcDatabaseOperations.java
+++ b/catalogs/catalog-jdbc-common/src/main/java/com/datastrato/gravitino/catalog/jdbc/operation/JdbcDatabaseOperations.java
@@ -101,7 +101,7 @@ protected Connection getConnection() throws SQLException {
    * Check whether it is a system database.
    *
    * @param dbName The name of the database.
-   * @return
+   * @return false for all cases.
    */
   protected boolean isSystemDatabase(String dbName) {
     return false;
diff --git a/catalogs/catalog-lakehouse-iceberg/src/main/java/com/datastrato/gravitino/catalog/lakehouse/iceberg/converter/ConvertUtil.java b/catalogs/catalog-lakehouse-iceberg/src/main/java/com/datastrato/gravitino/catalog/lakehouse/iceberg/converter/ConvertUtil.java
index 243cd6c638d..741a413a135 100644
--- a/catalogs/catalog-lakehouse-iceberg/src/main/java/com/datastrato/gravitino/catalog/lakehouse/iceberg/converter/ConvertUtil.java
+++ b/catalogs/catalog-lakehouse-iceberg/src/main/java/com/datastrato/gravitino/catalog/lakehouse/iceberg/converter/ConvertUtil.java
@@ -44,7 +44,7 @@ public static Type toIcebergType(
    * Convert the nested type of Iceberg to the type of gravitino.
    *
    * @param type Iceberg type of field.
-   * @return
+   * @return Gravitino type.
    */
   public static com.datastrato.gravitino.rel.types.Type formIcebergType(Type type) {
     return TypeUtil.visit(type, new FromIcebergType());
diff --git a/catalogs/catalog-lakehouse-iceberg/src/main/java/com/datastrato/gravitino/catalog/lakehouse/iceberg/converter/FromIcebergPartitionSpec.java b/catalogs/catalog-lakehouse-iceberg/src/main/java/com/datastrato/gravitino/catalog/lakehouse/iceberg/converter/FromIcebergPartitionSpec.java
index b42bbda01ba..10d81ff5d18 100644
--- a/catalogs/catalog-lakehouse-iceberg/src/main/java/com/datastrato/gravitino/catalog/lakehouse/iceberg/converter/FromIcebergPartitionSpec.java
+++ b/catalogs/catalog-lakehouse-iceberg/src/main/java/com/datastrato/gravitino/catalog/lakehouse/iceberg/converter/FromIcebergPartitionSpec.java
@@ -80,7 +80,7 @@ public Transform unknown(int fieldId, String sourceName, int sourceId, String tr
    *
    * @param partitionSpec
    * @param schema
-   * @return
+   * @return array of transforms for partition fields.
    */
   @VisibleForTesting
   public static Transform[] fromPartitionSpec(PartitionSpec partitionSpec, Schema schema) {
diff --git a/catalogs/catalog-lakehouse-iceberg/src/main/java/com/datastrato/gravitino/catalog/lakehouse/iceberg/converter/ToIcebergPartitionSpec.java b/catalogs/catalog-lakehouse-iceberg/src/main/java/com/datastrato/gravitino/catalog/lakehouse/iceberg/converter/ToIcebergPartitionSpec.java
index da53db3f325..8c0e56f99c8 100644
--- a/catalogs/catalog-lakehouse-iceberg/src/main/java/com/datastrato/gravitino/catalog/lakehouse/iceberg/converter/ToIcebergPartitionSpec.java
+++ b/catalogs/catalog-lakehouse-iceberg/src/main/java/com/datastrato/gravitino/catalog/lakehouse/iceberg/converter/ToIcebergPartitionSpec.java
@@ -21,7 +21,7 @@ public class ToIcebergPartitionSpec {
    * Convert iceberg table to iceberg partition spec through gravitino.
    *
    * @param icebergTable the iceberg table.
-   * @return
+   * @return a PartitionSpec
    */
   @VisibleForTesting
   public static PartitionSpec toPartitionSpec(IcebergTable icebergTable) {
diff --git a/catalogs/catalog-lakehouse-iceberg/src/main/java/com/datastrato/gravitino/catalog/lakehouse/iceberg/ops/IcebergTableOpsHelper.java b/catalogs/catalog-lakehouse-iceberg/src/main/java/com/datastrato/gravitino/catalog/lakehouse/iceberg/ops/IcebergTableOpsHelper.java
index ca05aec8c74..9e678f67a27 100644
--- a/catalogs/catalog-lakehouse-iceberg/src/main/java/com/datastrato/gravitino/catalog/lakehouse/iceberg/ops/IcebergTableOpsHelper.java
+++ b/catalogs/catalog-lakehouse-iceberg/src/main/java/com/datastrato/gravitino/catalog/lakehouse/iceberg/ops/IcebergTableOpsHelper.java
@@ -312,7 +312,7 @@ public IcebergTableChange buildIcebergTableChanges(
    * Therefore, we need to handle this difference here.
    *
    * @param namespace GravitinoNamespace
-   * @return
+   * @return Iceberg Namespace
    */
   public static Namespace getIcebergNamespace(com.datastrato.gravitino.Namespace namespace) {
     return getIcebergNamespace(namespace.level(namespace.length() - 1));
@@ -328,7 +328,7 @@ public static Namespace getIcebergNamespace(String... level) {
    *
    * @param namespace
    * @param name
-   * @return
+   * @return Iceberg TableIdentifier
    */
   public static TableIdentifier buildIcebergTableIdentifier(
       com.datastrato.gravitino.Namespace namespace, String name) {
@@ -341,7 +341,7 @@ public static TableIdentifier buildIcebergTableIdentifier(
    * `{namespace}.{table}`, so we need to perform truncation here.
    *
    * @param nameIdentifier GravitinoNameIdentifier
-   * @return
+   * @return Iceberg TableIdentifier
    */
   public static TableIdentifier buildIcebergTableIdentifier(NameIdentifier nameIdentifier) {
     String[] levels = nameIdentifier.namespace().levels();
diff --git a/common/src/main/java/com/datastrato/gravitino/json/JsonUtils.java b/common/src/main/java/com/datastrato/gravitino/json/JsonUtils.java
index 9489438bdb2..d81e345ba6f 100644
--- a/common/src/main/java/com/datastrato/gravitino/json/JsonUtils.java
+++ b/common/src/main/java/com/datastrato/gravitino/json/JsonUtils.java
@@ -170,7 +170,7 @@ abstract static class JsonArrayIterator<T> implements Iterator<T> {
     /**
      * Judge whether it has more elements in the JSON array.
      *
-     * @return
+     * @return true if the iteration has more elements.
      */
     @Override
     public boolean hasNext() {
@@ -180,7 +180,7 @@ public boolean hasNext() {
     /**
      * Get a next element from the JSON array.
      *
-     * @return
+     * @return the next element in the iteration.
      */
     @Override
     public T next() {
diff --git a/integration-test/src/test/java/com/datastrato/gravitino/integration/test/trino/TrinoQueryIT.java b/integration-test/src/test/java/com/datastrato/gravitino/integration/test/trino/TrinoQueryIT.java
index 06c3b685336..8a41a84bef8 100644
--- a/integration-test/src/test/java/com/datastrato/gravitino/integration/test/trino/TrinoQueryIT.java
+++ b/integration-test/src/test/java/com/datastrato/gravitino/integration/test/trino/TrinoQueryIT.java
@@ -239,7 +239,9 @@ void executeSqlFileWithCheckResult(
    *
    * @param expectResult
    * @param result
-   * @return
+   * @return false if the expected result is empty or the actual result does not match the expected.
+   *     For {@literal <BLANK_LINE>} case, return true if the actual result is empty. For {@literal
+   *     <QUERY_FAILED>} case, replace the placeholder with "^Query \\w+ failed.*: " and do match.
    */
   static boolean match(String expectResult, String result) {
     if (expectResult.isEmpty()) {