diff --git a/src/java_tools/buildjar/javatests/com/google/devtools/build/java/turbine/javac/JavacTurbineTest.java b/src/java_tools/buildjar/javatests/com/google/devtools/build/java/turbine/javac/JavacTurbineTest.java
index b4196a0..ab68d18 100644
--- a/src/java_tools/buildjar/javatests/com/google/devtools/build/java/turbine/javac/JavacTurbineTest.java
+++ b/src/java_tools/buildjar/javatests/com/google/devtools/build/java/turbine/javac/JavacTurbineTest.java
@@ -55,6 +55,7 @@
 import java.nio.file.attribute.BasicFileAttributes;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.Enumeration;
 import java.util.LinkedHashMap;
@@ -437,7 +438,7 @@
   }
 
   private void compileLib(
-      Path jar, Iterable<Path> classpath, Iterable<? extends JavaFileObject> units)
+      Path jar, Collection<Path> classpath, Iterable<? extends JavaFileObject> units)
       throws IOException {
     final Path outdir = temp.newFolder().toPath();
     JavacFileManager fm = new JavacFileManager(new Context(), false, UTF_8);