diff --git a/icu4j/main/tests/core/src/com/ibm/icu/dev/test/format/DateFormatRegressionTest.java b/icu4j/main/tests/core/src/com/ibm/icu/dev/test/format/DateFormatRegressionTest.java
index eacd70519d..9563fccad9 100644
--- a/icu4j/main/tests/core/src/com/ibm/icu/dev/test/format/DateFormatRegressionTest.java
+++ b/icu4j/main/tests/core/src/com/ibm/icu/dev/test/format/DateFormatRegressionTest.java
@@ -1479,5 +1479,13 @@ public class DateFormatRegressionTest extends com.ibm.icu.dev.test.TestFmwk {
         for (Thread t : threads) {
             t.start();
         }
+
+        for (Thread t : threads) {
+            try {
+                t.join();
+            } catch (InterruptedException e) {
+                errln(e.toString());
+            }
+        }
     }
 }