diff --git a/core/src/main/scala/org/apache/spark/deploy/master/Master.scala b/core/src/main/scala/org/apache/spark/deploy/master/Master.scala
index 4c12ab192079f..a58e14bdcdd34 100644
--- a/core/src/main/scala/org/apache/spark/deploy/master/Master.scala
+++ b/core/src/main/scala/org/apache/spark/deploy/master/Master.scala
@@ -85,7 +85,6 @@ private[spark] class Master(
   val masterSource = new MasterSource(this)
 
   val webUi = new MasterWebUI(this, webUiPort)
-  webUi.start()
 
   val masterPublicAddress = {
     val envVar = System.getenv("SPARK_PUBLIC_DNS")
@@ -116,6 +115,7 @@ private[spark] class Master(
     logInfo("Starting Spark master at " + masterUrl)
     // Listen for remote client disconnection events, since they don't go through Akka's watch()
     context.system.eventStream.subscribe(self, classOf[RemotingLifecycleEvent])
+    webUi.start()
     webUi.bind()
     masterWebUiUrl = "http://" + masterPublicAddress + ":" + webUi.boundPort
     context.system.scheduler.schedule(0 millis, WORKER_TIMEOUT millis, self, CheckForWorkerTimeOut)
diff --git a/core/src/main/scala/org/apache/spark/deploy/master/ui/MasterWebUI.scala b/core/src/main/scala/org/apache/spark/deploy/master/ui/MasterWebUI.scala
index fbcc76b3cc150..c8d51e44a4dff 100644
--- a/core/src/main/scala/org/apache/spark/deploy/master/ui/MasterWebUI.scala
+++ b/core/src/main/scala/org/apache/spark/deploy/master/ui/MasterWebUI.scala
@@ -35,6 +35,7 @@ class MasterWebUI(val master: Master, requestedPort: Int)
   val masterActorRef = master.self
   val timeout = AkkaUtils.askTimeout(master.conf)
 
+  /** Initialize all components of the server. Must be called before bind(). */
   def start() {
     attachPage(new ApplicationPage(this))
     attachPage(new IndexPage(this))
diff --git a/core/src/main/scala/org/apache/spark/deploy/worker/Worker.scala b/core/src/main/scala/org/apache/spark/deploy/worker/Worker.scala
index 97b5a37f1439c..e1921bcc0d025 100755
--- a/core/src/main/scala/org/apache/spark/deploy/worker/Worker.scala
+++ b/core/src/main/scala/org/apache/spark/deploy/worker/Worker.scala
@@ -122,10 +122,10 @@ private[spark] class Worker(
       host, port, cores, Utils.megabytesToString(memory)))
     logInfo("Spark home: " + sparkHome)
     createWorkDir()
+    context.system.eventStream.subscribe(self, classOf[RemotingLifecycleEvent])
     webUi = new WorkerWebUI(this, workDir, Some(webUiPort))
     webUi.start()
     webUi.bind()
-    context.system.eventStream.subscribe(self, classOf[RemotingLifecycleEvent])
     registerWithMaster()
 
     metricsSystem.registerSource(workerSource)
diff --git a/core/src/main/scala/org/apache/spark/deploy/worker/ui/WorkerWebUI.scala b/core/src/main/scala/org/apache/spark/deploy/worker/ui/WorkerWebUI.scala
index e0a60121cb65a..ae1b7ab014e6e 100644
--- a/core/src/main/scala/org/apache/spark/deploy/worker/ui/WorkerWebUI.scala
+++ b/core/src/main/scala/org/apache/spark/deploy/worker/ui/WorkerWebUI.scala
@@ -38,6 +38,7 @@ class WorkerWebUI(val worker: Worker, val workDir: File, requestedPort: Option[I
     worker.conf.get("worker.ui.port",  WorkerWebUI.DEFAULT_PORT).toInt)
   val timeout = AkkaUtils.askTimeout(worker.conf)
 
+  /** Initialize all components of the server. Must be called before bind(). */
   def start() {
     val logPage = new LogPage(this)
     attachPage(logPage)
diff --git a/core/src/main/scala/org/apache/spark/ui/WebUI.scala b/core/src/main/scala/org/apache/spark/ui/WebUI.scala
index 6f7385086b534..f20aec893c787 100644
--- a/core/src/main/scala/org/apache/spark/ui/WebUI.scala
+++ b/core/src/main/scala/org/apache/spark/ui/WebUI.scala
@@ -19,15 +19,16 @@ package org.apache.spark.ui
 
 import javax.servlet.http.HttpServletRequest
 
+import scala.collection.mutable.ArrayBuffer
+import scala.xml.Node
+
 import org.eclipse.jetty.servlet.ServletContextHandler
+import org.json4s.JsonAST.{JNothing, JValue}
 
 import org.apache.spark.SecurityManager
+import org.apache.spark.scheduler.SparkListener
 import org.apache.spark.ui.JettyUtils._
 import org.apache.spark.util.Utils
-import scala.collection.mutable.ArrayBuffer
-import org.apache.spark.scheduler.SparkListener
-import scala.xml.Node
-import org.json4s.JsonAST.{JNothing, JValue}
 
 /**
  * The top level component of the UI hierarchy that contains the server.
@@ -70,6 +71,9 @@ private[spark] abstract class WebUI(securityManager: SecurityManager, basePath:
   /** Return a list of handlers attached to this UI. */
   def getHandlers = handlers.toSeq
 
+  /** Initialize all components of the server. Must be called before bind(). */
+  def start()
+
   /**
    * Bind to the HTTP server behind this web interface.
    * Overridden implementation should set serverInfo.
@@ -101,6 +105,7 @@ private[spark] abstract class UITab(val prefix: String) {
     pages += page
   }
 
+  /** Initialize listener and attach pages. */
   def start()
 }
 
diff --git a/core/src/main/scala/org/apache/spark/ui/env/EnvironmentTab.scala b/core/src/main/scala/org/apache/spark/ui/env/EnvironmentTab.scala
index dd4ea2a2332a2..ad355e59a37aa 100644
--- a/core/src/main/scala/org/apache/spark/ui/env/EnvironmentTab.scala
+++ b/core/src/main/scala/org/apache/spark/ui/env/EnvironmentTab.scala
@@ -29,7 +29,7 @@ private[ui] class EnvironmentTab(parent: SparkUI) extends UITab("environment") {
     attachPage(new IndexPage(this))
   }
 
-  def environmentListener = {
+  def environmentListener: EnvironmentListener = {
     assert(listener.isDefined, "EnvironmentTab has not started yet!")
     listener.get.asInstanceOf[EnvironmentListener]
   }
diff --git a/core/src/main/scala/org/apache/spark/ui/exec/ExecutorsTab.scala b/core/src/main/scala/org/apache/spark/ui/exec/ExecutorsTab.scala
index 2b833c58c8e44..3941a1849b182 100644
--- a/core/src/main/scala/org/apache/spark/ui/exec/ExecutorsTab.scala
+++ b/core/src/main/scala/org/apache/spark/ui/exec/ExecutorsTab.scala
@@ -33,7 +33,7 @@ private[ui] class ExecutorsTab(parent: SparkUI) extends UITab("executors") {
     attachPage(new IndexPage(this))
   }
 
-  def executorsListener = {
+  def executorsListener: ExecutorsListener = {
     assert(listener.isDefined, "ExecutorsTab has not started yet!")
     listener.get.asInstanceOf[ExecutorsListener]
   }
diff --git a/core/src/main/scala/org/apache/spark/ui/exec/IndexPage.scala b/core/src/main/scala/org/apache/spark/ui/exec/IndexPage.scala
index fbbba2f63878f..9a711d773ae01 100644
--- a/core/src/main/scala/org/apache/spark/ui/exec/IndexPage.scala
+++ b/core/src/main/scala/org/apache/spark/ui/exec/IndexPage.scala
@@ -50,11 +50,11 @@ private[ui] class IndexPage(parent: ExecutorsTab) extends UIPage("") {
           </ul>
         </div>
       </div>
-        <div class = "row">
-          <div class="span12">
-            {execTable}
-          </div>
-        </div>;
+      <div class = "row">
+        <div class="span12">
+          {execTable}
+        </div>
+      </div>;
 
     UIUtils.headerSparkPage(
       content, basePath, appName, "Executors (" + execInfo.size + ")", Executors)
diff --git a/core/src/main/scala/org/apache/spark/ui/jobs/IndexPage.scala b/core/src/main/scala/org/apache/spark/ui/jobs/IndexPage.scala
index c600e58af004d..5c752793d2342 100644
--- a/core/src/main/scala/org/apache/spark/ui/jobs/IndexPage.scala
+++ b/core/src/main/scala/org/apache/spark/ui/jobs/IndexPage.scala
@@ -22,8 +22,8 @@ import javax.servlet.http.HttpServletRequest
 import scala.xml.{Node, NodeSeq}
 
 import org.apache.spark.scheduler.Schedulable
-import org.apache.spark.ui.Page._
 import org.apache.spark.ui.{UIPage, UIUtils}
+import org.apache.spark.ui.Page.Stages
 
 /** Page showing list of all ongoing and recently finished stages and pools */
 private[ui] class IndexPage(parent: JobProgressTab) extends UIPage("") {
diff --git a/core/src/main/scala/org/apache/spark/ui/jobs/JobProgressTab.scala b/core/src/main/scala/org/apache/spark/ui/jobs/JobProgressTab.scala
index c40b75d684510..611febe10c1aa 100644
--- a/core/src/main/scala/org/apache/spark/ui/jobs/JobProgressTab.scala
+++ b/core/src/main/scala/org/apache/spark/ui/jobs/JobProgressTab.scala
@@ -36,7 +36,7 @@ private[ui] class JobProgressTab(parent: SparkUI) extends UITab("stages") {
     attachPage(new PoolPage(this))
   }
 
-  def jobProgressListener = {
+  def jobProgressListener: JobProgressListener = {
     assert(listener.isDefined, "JobProgressTab has not started yet!")
     listener.get.asInstanceOf[JobProgressListener]
   }
diff --git a/core/src/main/scala/org/apache/spark/ui/jobs/PoolPage.scala b/core/src/main/scala/org/apache/spark/ui/jobs/PoolPage.scala
index 53200ecdd4fee..9382251d6e612 100644
--- a/core/src/main/scala/org/apache/spark/ui/jobs/PoolPage.scala
+++ b/core/src/main/scala/org/apache/spark/ui/jobs/PoolPage.scala
@@ -22,8 +22,8 @@ import javax.servlet.http.HttpServletRequest
 import scala.xml.Node
 
 import org.apache.spark.scheduler.{Schedulable, StageInfo}
-import org.apache.spark.ui.Page._
 import org.apache.spark.ui.{UIPage, UIUtils}
+import org.apache.spark.ui.Page.Stages
 
 /** Page showing specific pool details */
 private[ui] class PoolPage(parent: JobProgressTab) extends UIPage("pool") {
diff --git a/core/src/main/scala/org/apache/spark/ui/jobs/StagePage.scala b/core/src/main/scala/org/apache/spark/ui/jobs/StagePage.scala
index bd3d878b1567f..a4f6e5d69c515 100644
--- a/core/src/main/scala/org/apache/spark/ui/jobs/StagePage.scala
+++ b/core/src/main/scala/org/apache/spark/ui/jobs/StagePage.scala
@@ -22,8 +22,8 @@ import javax.servlet.http.HttpServletRequest
 
 import scala.xml.Node
 
-import org.apache.spark.ui.Page._
 import org.apache.spark.ui.{UIPage, UIUtils}
+import org.apache.spark.ui.Page.Stages
 import org.apache.spark.util.{Utils, Distribution}
 
 /** Page showing statistics and task list for a given stage */
diff --git a/core/src/main/scala/org/apache/spark/ui/jobs/StageTable.scala b/core/src/main/scala/org/apache/spark/ui/jobs/StageTable.scala
index e41e6c0ab7da6..d918feafd97d0 100644
--- a/core/src/main/scala/org/apache/spark/ui/jobs/StageTable.scala
+++ b/core/src/main/scala/org/apache/spark/ui/jobs/StageTable.scala
@@ -23,7 +23,7 @@ import scala.collection.mutable.HashMap
 import scala.xml.Node
 
 import org.apache.spark.scheduler.{StageInfo, TaskInfo}
-import org.apache.spark.ui.{WebUI, UIUtils}
+import org.apache.spark.ui.UIUtils
 import org.apache.spark.util.Utils
 
 /** Page showing list of all ongoing and recently finished stages */
diff --git a/core/src/main/scala/org/apache/spark/ui/storage/BlockManagerTab.scala b/core/src/main/scala/org/apache/spark/ui/storage/BlockManagerTab.scala
index d7fcd823a242f..2b9cf35fcde55 100644
--- a/core/src/main/scala/org/apache/spark/ui/storage/BlockManagerTab.scala
+++ b/core/src/main/scala/org/apache/spark/ui/storage/BlockManagerTab.scala
@@ -34,7 +34,7 @@ private[ui] class BlockManagerTab(parent: SparkUI) extends UITab("storage") {
     attachPage(new RddPage(this))
   }
 
-  def blockManagerListener = {
+  def blockManagerListener: BlockManagerListener = {
     assert(listener.isDefined, "BlockManagerTab has not started yet!")
     listener.get.asInstanceOf[BlockManagerListener]
   }
diff --git a/core/src/main/scala/org/apache/spark/ui/storage/IndexPage.scala b/core/src/main/scala/org/apache/spark/ui/storage/IndexPage.scala
index f06fdf7ce4d4c..7bfcf13c69c6b 100644
--- a/core/src/main/scala/org/apache/spark/ui/storage/IndexPage.scala
+++ b/core/src/main/scala/org/apache/spark/ui/storage/IndexPage.scala
@@ -22,8 +22,8 @@ import javax.servlet.http.HttpServletRequest
 import scala.xml.Node
 
 import org.apache.spark.storage.RDDInfo
-import org.apache.spark.ui.Page._
 import org.apache.spark.ui.{UIPage, UIUtils}
+import org.apache.spark.ui.Page.Storage
 import org.apache.spark.util.Utils
 
 /** Page showing list of RDD's currently stored in the cluster */
diff --git a/core/src/main/scala/org/apache/spark/ui/storage/RDDPage.scala b/core/src/main/scala/org/apache/spark/ui/storage/RDDPage.scala
index cb21754550494..35ccfd505a3ef 100644
--- a/core/src/main/scala/org/apache/spark/ui/storage/RDDPage.scala
+++ b/core/src/main/scala/org/apache/spark/ui/storage/RDDPage.scala
@@ -22,8 +22,8 @@ import javax.servlet.http.HttpServletRequest
 import scala.xml.Node
 
 import org.apache.spark.storage.{BlockId, BlockStatus, StorageStatus, StorageUtils}
-import org.apache.spark.ui.Page._
 import org.apache.spark.ui.{UIPage, UIUtils}
+import org.apache.spark.ui.Page.Storage
 import org.apache.spark.util.Utils
 
 /** Page showing storage details for a given RDD */