diff --git a/java/core/generate-test-sources-build.xml b/java/core/generate-test-sources-build.xml
index 68edf0bfc5..a818213300 100644
--- a/java/core/generate-test-sources-build.xml
+++ b/java/core/generate-test-sources-build.xml
@@ -19,6 +19,7 @@
         <arg value="${protobuf.source.dir}/google/protobuf/unittest_optimize_for.proto"/>
         <arg value="${protobuf.source.dir}/google/protobuf/unittest_proto3.proto"/>
         <arg value="${protobuf.source.dir}/google/protobuf/unittest_proto3_optional.proto"/>
+        <arg value="${protobuf.source.dir}/google/protobuf/unittest_retention.proto"/>
         <arg value="${protobuf.source.dir}/google/protobuf/unittest_well_known_types.proto"/>
         <arg value="${test.proto.dir}/com/google/protobuf/any_test.proto"/>
         <arg value="${test.proto.dir}/com/google/protobuf/cached_field_size_test.proto"/>