diff --git a/core/src/main/java/org/apache/calcite/util/format/postgresql/NumberFormatPattern.java b/core/src/main/java/org/apache/calcite/util/format/postgresql/NumberFormatPattern.java
index da175c8c0a5..57b4e8a4288 100644
--- a/core/src/main/java/org/apache/calcite/util/format/postgresql/NumberFormatPattern.java
+++ b/core/src/main/java/org/apache/calcite/util/format/postgresql/NumberFormatPattern.java
@@ -36,7 +36,7 @@ protected NumberFormatPattern(Function<ZonedDateTime, String> converter, String.
     this.patterns = patterns;
   }
 
-  @Nullable @Override public String convert(ParsePosition parsePosition, String formatString,
+  @Override public @Nullable String convert(ParsePosition parsePosition, String formatString,
       ZonedDateTime dateTime) {
     String formatStringTrimmed = formatString.substring(parsePosition.getIndex());
 
diff --git a/core/src/main/java/org/apache/calcite/util/format/postgresql/StringFormatPattern.java b/core/src/main/java/org/apache/calcite/util/format/postgresql/StringFormatPattern.java
index 6ebeb96661f..4162c4deb8d 100644
--- a/core/src/main/java/org/apache/calcite/util/format/postgresql/StringFormatPattern.java
+++ b/core/src/main/java/org/apache/calcite/util/format/postgresql/StringFormatPattern.java
@@ -33,7 +33,7 @@ protected StringFormatPattern(String... patterns) {
     this.patterns = patterns;
   }
 
-  @Nullable @Override public String convert(ParsePosition parsePosition, String formatString,
+  @Override public @Nullable String convert(ParsePosition parsePosition, String formatString,
       ZonedDateTime dateTime) {
     String formatStringTrimmed = formatString.substring(parsePosition.getIndex());