There are lots of boilerplate code that restricts the regression tests to run only in a specific locale, e.g., Locale.US., such as
```
Locale orig = Locale.getDefault();
try {
    Locale.setDefault(Locale.US);
    // test code
} finally {
    Locale.setDefault(orig);
}
```
These can be simplified with `@requires` tag, such as:
```
% git diff
diff --git a/test/jdk/TEST.ROOT b/test/jdk/TEST.ROOT
index 6b78ca255f5..05fd647e3c6 100644
--- a/test/jdk/TEST.ROOT
+++ b/test/jdk/TEST.ROOT
@@ -64,6 +64,10 @@ requires.properties= \
     vm.jvmci \
     docker.support \
     release.implementor \
+ user.language \
+ user.country \
+ user.script \
+ user.variant \
     jdk.containerized
 
 # Minimum jtreg version
diff --git a/test/jdk/java/util/Calendar/Bug6902861.java b/test/jdk/java/util/Calendar/Bug6902861.java
index b1aa86fdbd2..05bbaf16ab0 100644
--- a/test/jdk/java/util/Calendar/Bug6902861.java
+++ b/test/jdk/java/util/Calendar/Bug6902861.java
@@ -25,6 +25,7 @@
  * @test
  * @bug 6902861
  * @summary Test for a workaround when WEEK_OF_YEAR and YEAR are out of sync.
+ * @requires (user.language == "en") & (user.country == "US")
  * @modules jdk.localedata
  */
```