Addressed comments

sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/CheckpointFileManager.scala

@@ -16,12 +16,11 @@
  */
 package org.apache.spark.sql.execution.streaming
 
-import java.io.{FileSystem => _, _}
+import java.io.{FileNotFoundException, IOException, OutputStream}
 import java.util.{EnumSet, UUID}
 
 import scala.util.control.NonFatal
 
-import org.apache.commons.io.IOUtils
 import org.apache.hadoop.conf.Configuration
 import org.apache.hadoop.fs._
 import org.apache.hadoop.fs.local.{LocalFs, RawLocalFs}
@@ -228,7 +227,8 @@ class FileSystemBasedCheckpointFileManager(path: Path, hadoopConf: Configuration
   }
 
   override def createAtomic(
-      path: Path, overwriteIfPossible: Boolean): CancellableFSDataOutputStream = {
+      path: Path,
+      overwriteIfPossible: Boolean): CancellableFSDataOutputStream = {
     new RenameBasedFSDataOutputStream(this, path, overwriteIfPossible)
   }
 
@@ -311,7 +311,8 @@ class FileContextBasedCheckpointFileManager(path: Path, hadoopConf: Configuratio
   }
 
   override def createAtomic(
-      path: Path, overwriteIfPossible: Boolean): CancellableFSDataOutputStream = {
+      path: Path,
+      overwriteIfPossible: Boolean): CancellableFSDataOutputStream = {
     new RenameBasedFSDataOutputStream(this, path, overwriteIfPossible)
   }
 

sql/core/src/test/scala/org/apache/spark/sql/execution/streaming/CheckpointFileManagerSuite.scala

@@ -109,8 +109,8 @@ class CheckpointFileManagerSuite extends SparkFunSuite with SharedSparkSession {
   }
 
   test("CheckpointFileManager.create() should fallback from FileContext to FileSystem") {
-    import FakeFileSystem.scheme
-    spark.conf.set(s"fs.$scheme.impl", classOf[FakeFileSystem].getName)
+    import CheckpointFileManagerSuiteFileSystem.scheme
+    spark.conf.set(s"fs.$scheme.impl", classOf[CheckpointFileManagerSuiteFileSystem].getName)
     quietly {
       withTempDir { temp =>
         val metadataLog = new HDFSMetadataLog[String](spark, s"$scheme://${temp.toURI.getPath}")
@@ -177,15 +177,18 @@ object TestCheckpointFileManager {
 }
 
 
-/** FakeFileSystem to test fallback of the HDFSMetadataLog from FileContext to FileSystem API */
-private class FakeFileSystem extends RawLocalFileSystem {
-  import FakeFileSystem.scheme
+/**
+ * CheckpointFileManagerSuiteFileSystem to test fallback of the CheckpointFileManager
+ * from FileContext to FileSystem API.
+ */
+private class CheckpointFileManagerSuiteFileSystem extends RawLocalFileSystem {
+  import CheckpointFileManagerSuiteFileSystem.scheme
 
   override def getUri: URI = {
     URI.create(s"$scheme:///")
   }
 }
 
-private object FakeFileSystem {
-  val scheme = s"HDFSMetadataLogSuite${math.abs(Random.nextInt)}"
+private object CheckpointFileManagerSuiteFileSystem {
+  val scheme = s"CheckpointFileManagerSuiteFileSystem${math.abs(Random.nextInt)}"
 }

sql/core/src/test/scala/org/apache/spark/sql/execution/streaming/CompactibleFileStreamLogSuite.scala

@@ -27,10 +27,6 @@ import org.apache.spark.sql.test.SharedSQLContext
 
 class CompactibleFileStreamLogSuite extends SparkFunSuite with SharedSQLContext {
 
-  /** To avoid caching of FS objects */
-  override protected def sparkConf =
-    super.sparkConf.set(s"spark.hadoop.fs.$scheme.impl.disable.cache", "true")
-
   import CompactibleFileStreamLog._
 
   /** -- testing of `object CompactibleFileStreamLog` begins -- */

sql/core/src/test/scala/org/apache/spark/sql/execution/streaming/HDFSMetadataLogSuite.scala

@@ -18,27 +18,19 @@
 package org.apache.spark.sql.execution.streaming
 
 import java.io.File
-import java.net.URI
 import java.util.ConcurrentModificationException
 
 import scala.language.implicitConversions
-import scala.util.Random
 
-import org.apache.hadoop.fs._
 import org.scalatest.concurrent.Waiters._
 import org.scalatest.time.SpanSugar._
 
 import org.apache.spark.SparkFunSuite
-import org.apache.spark.sql.execution.streaming.FakeFileSystem._
 import org.apache.spark.sql.test.SharedSQLContext
 import org.apache.spark.util.UninterruptibleThread
 
 class HDFSMetadataLogSuite extends SparkFunSuite with SharedSQLContext {
 
-  /** To avoid caching of FS objects */
-  override protected def sparkConf =
-    super.sparkConf.set(s"spark.hadoop.fs.$scheme.impl.disable.cache", "true")
-
   private implicit def toOption[A](a: A): Option[A] = Option(a)
 
   test("HDFSMetadataLog: basic") {