diff --git a/hadoop-mapreduce-project/CHANGES.txt b/hadoop-mapreduce-project/CHANGES.txt
index edf69554d5..c378d2b025 100644
--- a/hadoop-mapreduce-project/CHANGES.txt
+++ b/hadoop-mapreduce-project/CHANGES.txt
@@ -1299,6 +1299,9 @@ Release 0.23.0 - Unreleased
    MAPREDUCE-2985. Fixed findbugs warnings in ResourceLocalizationService.
    (Thomas Graves via acmurthy)
 
+   MAPREDUCE-2874. Fix formatting of ApplicationId in web-ui. (Eric Payne via
+   acmurthy)
+
 Release 0.22.0 - Unreleased
 
   INCOMPATIBLE CHANGES
diff --git a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app/src/main/java/org/apache/hadoop/mapreduce/v2/app/webapp/AppController.java b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app/src/main/java/org/apache/hadoop/mapreduce/v2/app/webapp/AppController.java
index 1002d4a0e3..3c3ba74651 100644
--- a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app/src/main/java/org/apache/hadoop/mapreduce/v2/app/webapp/AppController.java
+++ b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app/src/main/java/org/apache/hadoop/mapreduce/v2/app/webapp/AppController.java
@@ -47,7 +47,7 @@ protected AppController(App app, Configuration conf, RequestContext ctx,
       String title) {
     super(ctx);
     this.app = app;
-    set(APP_ID, Apps.toString(app.context.getApplicationID()));
+    set(APP_ID, app.context.getApplicationID().toString());
     set(RM_WEB, YarnConfiguration.getRMWebAppURL(conf));
   }
 
diff --git a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app/src/test/java/org/apache/hadoop/mapreduce/v2/app/webapp/TestAMWebApp.java b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app/src/test/java/org/apache/hadoop/mapreduce/v2/app/webapp/TestAMWebApp.java
index 474e39d40d..c5938e8ca1 100644
--- a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app/src/test/java/org/apache/hadoop/mapreduce/v2/app/webapp/TestAMWebApp.java
+++ b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app/src/test/java/org/apache/hadoop/mapreduce/v2/app/webapp/TestAMWebApp.java
@@ -108,7 +108,7 @@ public long getStartTime() {
     Injector injector = WebAppTests.createMockInjector(AppContext.class, ctx);
     AppController controller = injector.getInstance(AppController.class);
     controller.index();
-    assertEquals(Apps.toString(ctx.appID), controller.get(APP_ID,""));
+    assertEquals(ctx.appID.toString(), controller.get(APP_ID,""));
   }
 
   @Test public void testAppView() {
diff --git a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-hs/src/test/java/org/apache/hadoop/mapreduce/v2/hs/webapp/TestHSWebApp.java b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-hs/src/test/java/org/apache/hadoop/mapreduce/v2/hs/webapp/TestHSWebApp.java
index 736987a468..8d25549517 100644
--- a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-hs/src/test/java/org/apache/hadoop/mapreduce/v2/hs/webapp/TestHSWebApp.java
+++ b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-hs/src/test/java/org/apache/hadoop/mapreduce/v2/hs/webapp/TestHSWebApp.java
@@ -107,7 +107,7 @@ public long getStartTime() {
     Injector injector = WebAppTests.createMockInjector(AppContext.class, ctx);
     HsController controller = injector.getInstance(HsController.class);
     controller.index();
-    assertEquals(Apps.toString(ctx.appID), controller.get(APP_ID,""));
+    assertEquals(ctx.appID.toString(), controller.get(APP_ID,""));
   }
 
   @Test public void testJobView() {
diff --git a/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/util/Apps.java b/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/util/Apps.java
index fcb3f956e0..90e181576c 100644
--- a/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/util/Apps.java
+++ b/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/util/Apps.java
@@ -33,10 +33,6 @@ public class Apps {
   public static final String APP = "app";
   public static final String ID = "ID";
 
-  public static String toString(ApplicationId id) {
-    return _join("app", id.getClusterTimestamp(), id.getId());
-  }
-
   public static ApplicationId toAppID(String aid) {
     Iterator<String> it = _split(aid).iterator();
     return toAppID(APP, aid, it);
diff --git a/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/webapp/AppsBlock.java b/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/webapp/AppsBlock.java
index cf4d94b1ee..94649923cb 100644
--- a/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/webapp/AppsBlock.java
+++ b/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/webapp/AppsBlock.java
@@ -56,7 +56,7 @@ class AppsBlock extends HtmlBlock {
         tbody();
     int i = 0;
     for (RMApp app : list.apps.values()) {
-      String appId = Apps.toString(app.getApplicationId());
+      String appId = app.getApplicationId().toString();
       String trackingUrl = app.getTrackingUrl();
       String ui = trackingUrl == null || trackingUrl.isEmpty() ? "UNASSIGNED" :
           (app.getFinishTime() == 0 ? "ApplicationMaster" : "JobHistory");
diff --git a/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/webapp/AppsList.java b/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/webapp/AppsList.java
index a0dfa783a6..ba6b0ea231 100644
--- a/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/webapp/AppsList.java
+++ b/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/webapp/AppsList.java
@@ -60,7 +60,7 @@ void toDataTableArrays(PrintWriter out) {
       } else {
         out.append(",\n");
       }
-      String appID = Apps.toString(app.getApplicationId());
+      String appID = app.getApplicationId().toString();
       String trackingUrl = app.getTrackingUrl();
       String ui = trackingUrl == null ? "UNASSIGNED" :
           (app.getFinishTime() == 0 ? "ApplicationMaster" : "JobHistory");