[MINOR] Fix Typos 'a -> an'

## What changes were proposed in this pull request?

`a` -> `an`

I use regex to generate potential error lines:
`grep -in ' a [aeiou]' mllib/src/main/scala/org/apache/spark/ml/*/*scala`
and review them line by line.

## How was this patch tested?

local build
`lint-java` checking

Author: Zheng RuiFeng <ruifengz@foxmail.com>

Closes #13317 from zhengruifeng/a_an.

7 files changed, 8 insertions, 8 deletions

diff --git a/core/src/main/scala/org/apache/spark/HeartbeatReceiver.scala b/core/src/main/scala/org/apache/spark/HeartbeatReceiver.scala
index 73495a8d7d..c3764ac671 100644
--- a/core/src/main/scala/org/apache/spark/HeartbeatReceiver.scala
+++ b/core/src/main/scala/org/apache/spark/HeartbeatReceiver.scala
@@ -166,7 +166,7 @@ private[spark] class HeartbeatReceiver(sc: SparkContext, clock: Clock)
   }
 
   /**
-   * Send ExecutorRemoved to the event loop to remove a executor. Only for test.
+   * Send ExecutorRemoved to the event loop to remove an executor. Only for test.
    *
    * @return if HeartbeatReceiver is stopped, return None. Otherwise, return a Some(Future) that
    *         indicate if this operation is successful.
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 faed4f4dc9..f8aac3008c 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
@@ -929,7 +929,7 @@ private[deploy] class Master(
     exec.state = ExecutorState.KILLED
   }
 
-  /** Generate a new app ID given a app's submission date */
+  /** Generate a new app ID given an app's submission date */
   private def newApplicationId(submitDate: Date): String = {
     val appId = "app-%s-%04d".format(createDateFormat.format(submitDate), nextAppNumber)
     nextAppNumber += 1
diff --git a/core/src/main/scala/org/apache/spark/memory/ExecutionMemoryPool.scala b/core/src/main/scala/org/apache/spark/memory/ExecutionMemoryPool.scala
index f8167074c6..f1915857ea 100644
--- a/core/src/main/scala/org/apache/spark/memory/ExecutionMemoryPool.scala
+++ b/core/src/main/scala/org/apache/spark/memory/ExecutionMemoryPool.scala
@@ -24,7 +24,7 @@ import scala.collection.mutable
 import org.apache.spark.internal.Logging
 
 /**
- * Implements policies and bookkeeping for sharing a adjustable-sized pool of memory between tasks.
+ * Implements policies and bookkeeping for sharing an adjustable-sized pool of memory between tasks.
  *
  * Tries to ensure that each task gets a reasonable share of memory, instead of some task ramping up
  * to a large amount first and then causing others to spill to disk repeatedly.
diff --git a/core/src/main/scala/org/apache/spark/rdd/PairRDDFunctions.scala b/core/src/main/scala/org/apache/spark/rdd/PairRDDFunctions.scala
index a714237601..104e0cb371 100644
--- a/core/src/main/scala/org/apache/spark/rdd/PairRDDFunctions.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/PairRDDFunctions.scala
@@ -1054,7 +1054,7 @@ class PairRDDFunctions[K, V](self: RDD[(K, V)])
       val warningMessage =
         s"$outputCommitterClass may be an output committer that writes data directly to " +
           "the final location. Because speculation is enabled, this output committer may " +
-          "cause data loss (see the case in SPARK-10063). If possible, please use a output " +
+          "cause data loss (see the case in SPARK-10063). If possible, please use an output " +
           "committer that does not have this behavior (e.g. FileOutputCommitter)."
       logWarning(warningMessage)
     }
@@ -1142,7 +1142,7 @@ class PairRDDFunctions[K, V](self: RDD[(K, V)])
       val warningMessage =
         s"$outputCommitterClass may be an output committer that writes data directly to " +
           "the final location. Because speculation is enabled, this output committer may " +
-          "cause data loss (see the case in SPARK-10063). If possible, please use a output " +
+          "cause data loss (see the case in SPARK-10063). If possible, please use an output " +
           "committer that does not have this behavior (e.g. FileOutputCommitter)."
       logWarning(warningMessage)
     }
diff --git a/core/src/main/scala/org/apache/spark/rpc/netty/Inbox.scala b/core/src/main/scala/org/apache/spark/rpc/netty/Inbox.scala
index fffbd5cd44..ae4a600351 100644
--- a/core/src/main/scala/org/apache/spark/rpc/netty/Inbox.scala
+++ b/core/src/main/scala/org/apache/spark/rpc/netty/Inbox.scala
@@ -52,7 +52,7 @@ private[netty] case class RemoteProcessConnectionError(cause: Throwable, remoteA
   extends InboxMessage
 
 /**
- * A inbox that stores messages for an [[RpcEndpoint]] and posts messages to it thread-safely.
+ * An inbox that stores messages for an [[RpcEndpoint]] and posts messages to it thread-safely.
  */
 private[netty] class Inbox(
     val endpointRef: NettyRpcEndpointRef,
diff --git a/core/src/main/scala/org/apache/spark/scheduler/ExecutorLossReason.scala b/core/src/main/scala/org/apache/spark/scheduler/ExecutorLossReason.scala
index 7e1197d742..642bf81ac0 100644
--- a/core/src/main/scala/org/apache/spark/scheduler/ExecutorLossReason.scala
+++ b/core/src/main/scala/org/apache/spark/scheduler/ExecutorLossReason.scala
@@ -20,7 +20,7 @@ package org.apache.spark.scheduler
 import org.apache.spark.executor.ExecutorExitCode
 
 /**
- * Represents an explanation for a executor or whole slave failing or exiting.
+ * Represents an explanation for an executor or whole slave failing or exiting.
  */
 private[spark]
 class ExecutorLossReason(val message: String) extends Serializable {
diff --git a/core/src/main/scala/org/apache/spark/serializer/SerializerManager.scala b/core/src/main/scala/org/apache/spark/serializer/SerializerManager.scala
index 745ef12691..9dc274c9fe 100644
--- a/core/src/main/scala/org/apache/spark/serializer/SerializerManager.scala
+++ b/core/src/main/scala/org/apache/spark/serializer/SerializerManager.scala
@@ -134,7 +134,7 @@ private[spark] class SerializerManager(defaultSerializer: Serializer, conf: Spar
   }
 
   /**
-   * Deserializes a InputStream into an iterator of values and disposes of it when the end of
+   * Deserializes an InputStream into an iterator of values and disposes of it when the end of
    * the iterator is reached.
    */
   def dataDeserializeStream[T: ClassTag](