diff --git a/dexlib2/src/main/java/org/jf/dexlib2/analysis/ClassProto.java b/dexlib2/src/main/java/org/jf/dexlib2/analysis/ClassProto.java
old mode 100644
new mode 100755
index bee3049a..70e37937
--- a/dexlib2/src/main/java/org/jf/dexlib2/analysis/ClassProto.java
+++ b/dexlib2/src/main/java/org/jf/dexlib2/analysis/ClassProto.java
@@ -31,6 +31,7 @@
 
 package org.jf.dexlib2.analysis;
 
+import com.google.common.base.Joiner;
 import com.google.common.base.Predicates;
 import com.google.common.base.Supplier;
 import com.google.common.base.Suppliers;
@@ -219,7 +220,7 @@ public class ClassProto implements TypeProto {
 
         if (!interfacesFullyResolved) {
             throw new UnresolvedClassException("Interfaces for class %s not fully resolved: %s", getType(),
-                    String.join(",", getUnresolvedInterfaces()));
+                    Joiner.on(',').join(getUnresolvedInterfaces()));
         }
 
         return directInterfaces;