diff --git a/docs/tuning.md b/docs/tuning.md
index e2fdcfe6a37d99970dcfe0ccf1ccf6ff1e971ba5..efaac9d3d405fd84ccac8c34b49df2fd5317a14b 100644
--- a/docs/tuning.md
+++ b/docs/tuning.md
@@ -51,7 +51,7 @@ To register your own custom classes with Kryo, use the `registerKryoClasses` met
 
 {% highlight scala %}
 val conf = new SparkConf().setMaster(...).setAppName(...)
-conf.registerKryoClasses(Seq(classOf[MyClass1], classOf[MyClass2]))
+conf.registerKryoClasses(Array(classOf[MyClass1], classOf[MyClass2]))
 val sc = new SparkContext(conf)
 {% endhighlight %}