--- a/truffle/com.oracle.truffle.api.interop/src/com/oracle/truffle/api/interop/impl/ReadOnlyArrayList.java	Mon Dec 14 15:07:19 2015 +0100
+++ b/truffle/com.oracle.truffle.api.interop/src/com/oracle/truffle/api/interop/impl/ReadOnlyArrayList.java	Wed Dec 16 12:31:17 2015 +0100
@@ -211,6 +211,25 @@
         return new ReadOnlyArrayList<>(arr, first + fromIndex, first + toIndex);
     }
 
+    @Override
+    public String toString() {
+        Iterator<T> it = iterator();
+        if (!it.hasNext()) {
+            return "[]";
+        }
+
+        StringBuilder sb = new StringBuilder();
+        sb.append('[');
+        for (;;) {
+            T e = it.next();
+            sb.append(e == this ? "(this Collection)" : e);
+            if (!it.hasNext()) {
+                return sb.append(']').toString();
+            }
+            sb.append(',').append(' ');
+        }
+    }
+
     private final class LI implements ListIterator<T>, Iterator<T> {
         private int index;