diff --git a/core/src/main/resources/org/apache/spark/ui/static/executorspage.js b/core/src/main/resources/org/apache/spark/ui/static/executorspage.js
index b7fbe0492b6d7..bf6af9b2cc922 100644
--- a/core/src/main/resources/org/apache/spark/ui/static/executorspage.js
+++ b/core/src/main/resources/org/apache/spark/ui/static/executorspage.js
@@ -126,7 +126,6 @@ function totalDurationAlpha(totalGCTime, totalDuration) {
     (Math.min(totalGCTime / totalDuration + 0.5, 1)) : 1;
 }
 
-// When GCTimePercent is edited change ToolTips.TASK_TIME to match
 var GCTimePercent = 0.1;
 
 function totalDurationStyle(totalGCTime, totalDuration) {
diff --git a/core/src/main/scala/org/apache/spark/deploy/history/ApplicationCache.scala b/core/src/main/scala/org/apache/spark/deploy/history/ApplicationCache.scala
index 829631a04546e..909f5ea937cee 100644
--- a/core/src/main/scala/org/apache/spark/deploy/history/ApplicationCache.scala
+++ b/core/src/main/scala/org/apache/spark/deploy/history/ApplicationCache.scala
@@ -394,7 +394,6 @@ private[history] class ApplicationCacheCheckFilter(
     val httpRequest = request.asInstanceOf[HttpServletRequest]
     val httpResponse = response.asInstanceOf[HttpServletResponse]
     val requestURI = httpRequest.getRequestURI
-    val operation = httpRequest.getMethod
 
     // if the request is for an attempt, check to see if it is in need of delete/refresh
     // and have the cache update the UI if so
diff --git a/core/src/main/scala/org/apache/spark/rdd/HadoopRDD.scala b/core/src/main/scala/org/apache/spark/rdd/HadoopRDD.scala
index 0d905b46953c0..cad107256c58c 100644
--- a/core/src/main/scala/org/apache/spark/rdd/HadoopRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/HadoopRDD.scala
@@ -404,9 +404,6 @@ private[spark] object HadoopRDD extends Logging {
    */
   val CONFIGURATION_INSTANTIATION_LOCK = new Object()
 
-  /** Update the input bytes read metric each time this number of records has been read */
-  val RECORDS_BETWEEN_BYTES_READ_METRIC_UPDATES = 256
-
   /**
    * The three methods below are helpers for accessing the local map, a property of the SparkEnv of
    * the local process.
diff --git a/core/src/main/scala/org/apache/spark/ui/JettyUtils.scala b/core/src/main/scala/org/apache/spark/ui/JettyUtils.scala
index d8119fb949847..9582bdbf52641 100644
--- a/core/src/main/scala/org/apache/spark/ui/JettyUtils.scala
+++ b/core/src/main/scala/org/apache/spark/ui/JettyUtils.scala
@@ -590,11 +590,6 @@ private class ProxyRedirectHandler(_proxyUri: String) extends HandlerWrapper {
     override def sendRedirect(location: String): Unit = {
       val newTarget = if (location != null) {
         val target = new URI(location)
-        val path = if (target.getPath().startsWith("/")) {
-          target.getPath()
-        } else {
-          req.getRequestURI().stripSuffix("/") + "/" + target.getPath()
-        }
         // The target path should already be encoded, so don't re-encode it, just the
         // proxy address part.
         val proxyBase = UIUtils.uiRoot(req)
diff --git a/core/src/main/scala/org/apache/spark/ui/ToolTips.scala b/core/src/main/scala/org/apache/spark/ui/ToolTips.scala
index 587046676ff13..b80fba396b33a 100644
--- a/core/src/main/scala/org/apache/spark/ui/ToolTips.scala
+++ b/core/src/main/scala/org/apache/spark/ui/ToolTips.scala
@@ -35,10 +35,6 @@ private[spark] object ToolTips {
 
   val OUTPUT = "Bytes written to Hadoop."
 
-  val STORAGE_MEMORY =
-    "Memory used / total available memory for storage of data " +
-      "like RDD partitions cached in memory. "
-
   val SHUFFLE_WRITE =
     "Bytes and records written to disk in order to be read by a shuffle in a future stage."
 
@@ -88,9 +84,6 @@ private[spark] object ToolTips {
        also create multiple RDDs internally. Cached RDDs are shown in green.
     """
 
-  val TASK_TIME =
-  "Shaded red when garbage collection (GC) time is over 10% of task time"
-
   val APPLICATION_EXECUTOR_LIMIT =
     """Maximum number of executors that this application will use. This limit is finite only when
        dynamic allocation is enabled. The number of granted executors may exceed the limit