diff --git a/src/main/java/com/android/tools/r8/StringConsumer.java b/src/main/java/com/android/tools/r8/StringConsumer.java
index cccb72e..8dacc57 100644
--- a/src/main/java/com/android/tools/r8/StringConsumer.java
+++ b/src/main/java/com/android/tools/r8/StringConsumer.java
@@ -16,6 +16,7 @@
 import java.nio.file.Path;
 
 /** Interface for receiving String resource. */
+@KeepForSubclassing
 public interface StringConsumer {
 
   /**