diff --git a/core/java/android/webkit/HttpAuthHandler.java b/core/java/android/webkit/HttpAuthHandler.java
index 5353bc6983ee7..715fc9abe4ba0 100644
--- a/core/java/android/webkit/HttpAuthHandler.java
+++ b/core/java/android/webkit/HttpAuthHandler.java
@@ -41,6 +41,9 @@ public class HttpAuthHandler extends Handler {
      * are suitable for use. Credentials are not suitable if they have
      * previously been rejected by the server for the current request.
      *
+     * <p class="note"><b>Note:</b> The host application must call this method
+     * on the host application's UI Thread.
+     *
      * @return whether the credentials are suitable for use
      * @see WebView#getHttpAuthUsernamePassword
      */
@@ -50,6 +53,9 @@ public class HttpAuthHandler extends Handler {
 
     /**
      * Instructs the WebView to cancel the authentication request.
+     *
+     * <p class="note"><b>Note:</b> The host application must call this method
+     * on the host application's UI Thread.
      */
     public void cancel() {
     }
@@ -58,6 +64,9 @@ public class HttpAuthHandler extends Handler {
      * Instructs the WebView to proceed with the authentication with the given
      * credentials. Credentials for use with this method can be retrieved from
      * the WebView's store using {@link WebView#getHttpAuthUsernamePassword}.
+     *
+     * <p class="note"><b>Note:</b> The host application must call this method
+     * on the host application's UI Thread.
      */
     public void proceed(String username, String password) {
     }
diff --git a/core/java/android/webkit/WebViewClient.java b/core/java/android/webkit/WebViewClient.java
index 7b6e1a3704790..55f09f110f883 100644
--- a/core/java/android/webkit/WebViewClient.java
+++ b/core/java/android/webkit/WebViewClient.java
@@ -455,6 +455,9 @@ public class WebViewClient {
      * {@link HttpAuthHandler} to set the WebView's response to the request.
      * The default behavior is to cancel the request.
      *
+     * <p class="note"><b>Note:</b> The supplied HttpAuthHandler must be used on
+     * the UI thread.
+     *
      * @param view the WebView that is initiating the callback
      * @param handler the HttpAuthHandler used to set the WebView's response
      * @param host the host requiring authentication