diff --git a/core/src/test/java/com/scalar/db/transaction/consensuscommit/CoordinatorGroupCommitterTest.java b/core/src/test/java/com/scalar/db/transaction/consensuscommit/CoordinatorGroupCommitterTest.java
index 40d2491c5c..0d123cd3ae 100644
--- a/core/src/test/java/com/scalar/db/transaction/consensuscommit/CoordinatorGroupCommitterTest.java
+++ b/core/src/test/java/com/scalar/db/transaction/consensuscommit/CoordinatorGroupCommitterTest.java
@@ -258,8 +258,9 @@ void remove_GivenAllFullTxIds_ShouldRemoveAll() throws Exception {
     }
   }
 
+  @SuppressWarnings("ClassCanBeStatic")
   @Nested
-  static class CoordinatorGroupCommitKeyManipulatorTest {
+  class CoordinatorGroupCommitKeyManipulatorTest {
     private final CoordinatorGroupCommitKeyManipulator keyManipulator =
         new CoordinatorGroupCommitKeyManipulator();