diff --git a/resource-managers/mesos/src/main/scala/org/apache/spark/scheduler/cluster/mesos/MesosClusterSchedulerSource.scala b/resource-managers/mesos/src/main/scala/org/apache/spark/scheduler/cluster/mesos/MesosClusterSchedulerSource.scala
index 1fe94974c8e36e5c68cb47fc2b74e8226a6b8319..76aded4edb43190828acce80a264eb78dafff889 100644
--- a/resource-managers/mesos/src/main/scala/org/apache/spark/scheduler/cluster/mesos/MesosClusterSchedulerSource.scala
+++ b/resource-managers/mesos/src/main/scala/org/apache/spark/scheduler/cluster/mesos/MesosClusterSchedulerSource.scala
@@ -23,8 +23,9 @@ import org.apache.spark.metrics.source.Source
 
 private[mesos] class MesosClusterSchedulerSource(scheduler: MesosClusterScheduler)
   extends Source {
-  override def sourceName: String = "mesos_cluster"
-  override def metricRegistry: MetricRegistry = new MetricRegistry()
+
+  override val sourceName: String = "mesos_cluster"
+  override val metricRegistry: MetricRegistry = new MetricRegistry()
 
   metricRegistry.register(MetricRegistry.name("waitingDrivers"), new Gauge[Int] {
     override def getValue: Int = scheduler.getQueuedDriversSize