address comment

Author: xuyangzhong

flink-table/flink-table-planner/src/test/java/org/apache/flink/table/planner/plan/utils/DeltaJoinUtilTest.java

@@ -30,7 +30,6 @@
 import org.apache.calcite.util.ImmutableBitSet;
 import org.junit.jupiter.api.Test;
 
-import java.util.Arrays;
 import java.util.List;
 import java.util.Set;
 import java.util.stream.Collectors;
@@ -40,10 +39,10 @@
 import static org.assertj.core.api.Assertions.assertThat;
 
 /** Test for {@link DeltaJoinUtil}. */
-public class DeltaJoinUtilTest {
+class DeltaJoinUtilTest {
 
     @Test
-    public void testIsFilterOnOneSetOfUpsertKeys() {
+    void testIsFilterOnOneSetOfUpsertKeys() {
         FlinkTypeFactory typeFactory =
                 new FlinkTypeFactory(
                         Thread.currentThread().getContextClassLoader(), FlinkTypeSystem.INSTANCE);
@@ -88,6 +87,6 @@ public void testIsFilterOnOneSetOfUpsertKeys() {
     }
 
     private Set<ImmutableBitSet> buildUpsertKeys(ImmutableBitSet... upsertKeys) {
-        return Arrays.stream(upsertKeys).collect(Collectors.toSet());
+        return Set.of(upsertKeys);
     }
 }