[SPARK-18076][CORE][SQL] Fix default Locale used in DateFormat, NumberFormat to Locale.US

## What changes were proposed in this pull request?

Fix `Locale.US` for all usages of `DateFormat`, `NumberFormat`
## How was this patch tested?

Existing tests.

Author: Sean Owen <sowen@cloudera.com>

Closes #15610 from srowen/SPARK-18076.

31 files changed, 103 insertions, 96 deletions

diff --git a/core/src/main/scala/org/apache/spark/SparkHadoopWriter.scala b/core/src/main/scala/org/apache/spark/SparkHadoopWriter.scala
index 6550d703bc..7f75a393bf 100644
--- a/core/src/main/scala/org/apache/spark/SparkHadoopWriter.scala
+++ b/core/src/main/scala/org/apache/spark/SparkHadoopWriter.scala
@@ -20,7 +20,7 @@ package org.apache.spark
 import java.io.IOException
 import java.text.NumberFormat
 import java.text.SimpleDateFormat
-import java.util.Date
+import java.util.{Date, Locale}
 
 import org.apache.hadoop.fs.FileSystem
 import org.apache.hadoop.fs.Path
@@ -67,12 +67,12 @@ class SparkHadoopWriter(jobConf: JobConf) extends Logging with Serializable {
 
   def setup(jobid: Int, splitid: Int, attemptid: Int) {
     setIDs(jobid, splitid, attemptid)
-    HadoopRDD.addLocalConfiguration(new SimpleDateFormat("yyyyMMddHHmmss").format(now),
+    HadoopRDD.addLocalConfiguration(new SimpleDateFormat("yyyyMMddHHmmss", Locale.US).format(now),
       jobid, splitID, attemptID, conf.value)
   }
 
   def open() {
-    val numfmt = NumberFormat.getInstance()
+    val numfmt = NumberFormat.getInstance(Locale.US)
     numfmt.setMinimumIntegerDigits(5)
     numfmt.setGroupingUsed(false)
 
@@ -162,7 +162,7 @@ class SparkHadoopWriter(jobConf: JobConf) extends Logging with Serializable {
 private[spark]
 object SparkHadoopWriter {
   def createJobID(time: Date, id: Int): JobID = {
-    val formatter = new SimpleDateFormat("yyyyMMddHHmmss")
+    val formatter = new SimpleDateFormat("yyyyMMddHHmmss", Locale.US)
     val jobtrackerID = formatter.format(time)
     new JobID(jobtrackerID, id)
   }
diff --git a/core/src/main/scala/org/apache/spark/deploy/SparkHadoopUtil.scala b/core/src/main/scala/org/apache/spark/deploy/SparkHadoopUtil.scala
index 3f54ecc17a..23156072c3 100644
--- a/core/src/main/scala/org/apache/spark/deploy/SparkHadoopUtil.scala
+++ b/core/src/main/scala/org/apache/spark/deploy/SparkHadoopUtil.scala
@@ -21,7 +21,7 @@ import java.io.IOException
 import java.lang.reflect.Method
 import java.security.PrivilegedExceptionAction
 import java.text.DateFormat
-import java.util.{Arrays, Comparator, Date}
+import java.util.{Arrays, Comparator, Date, Locale}
 
 import scala.collection.JavaConverters._
 import scala.util.control.NonFatal
@@ -357,7 +357,7 @@ class SparkHadoopUtil extends Logging {
    * @return a printable string value.
    */
   private[spark] def tokenToString(token: Token[_ <: TokenIdentifier]): String = {
-    val df = DateFormat.getDateTimeInstance(DateFormat.SHORT, DateFormat.SHORT)
+    val df = DateFormat.getDateTimeInstance(DateFormat.SHORT, DateFormat.SHORT, Locale.US)
     val buffer = new StringBuilder(128)
     buffer.append(token.toString)
     try {
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 8c91aa1516..4618e6117a 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
@@ -18,7 +18,7 @@
 package org.apache.spark.deploy.master
 
 import java.text.SimpleDateFormat
-import java.util.Date
+import java.util.{Date, Locale}
 import java.util.concurrent.{ScheduledFuture, TimeUnit}
 
 import scala.collection.mutable.{ArrayBuffer, HashMap, HashSet}
@@ -51,7 +51,8 @@ private[deploy] class Master(
 
   private val hadoopConf = SparkHadoopUtil.get.newConfiguration(conf)
 
-  private def createDateFormat = new SimpleDateFormat("yyyyMMddHHmmss") // For application IDs
+  // For application IDs
+  private def createDateFormat = new SimpleDateFormat("yyyyMMddHHmmss", Locale.US)
 
   private val WORKER_TIMEOUT_MS = conf.getLong("spark.worker.timeout", 60) * 1000
   private val RETAINED_APPLICATIONS = conf.getInt("spark.deploy.retainedApplications", 200)
diff --git a/core/src/main/scala/org/apache/spark/deploy/worker/Worker.scala b/core/src/main/scala/org/apache/spark/deploy/worker/Worker.scala
index 0bedd9a20a..8b1c6bf2e5 100755
--- a/core/src/main/scala/org/apache/spark/deploy/worker/Worker.scala
+++ b/core/src/main/scala/org/apache/spark/deploy/worker/Worker.scala
@@ -20,7 +20,7 @@ package org.apache.spark.deploy.worker
 import java.io.File
 import java.io.IOException
 import java.text.SimpleDateFormat
-import java.util.{Date, UUID}
+import java.util.{Date, Locale, UUID}
 import java.util.concurrent._
 import java.util.concurrent.{Future => JFuture, ScheduledFuture => JScheduledFuture}
 
@@ -68,7 +68,7 @@ private[deploy] class Worker(
     ThreadUtils.newDaemonSingleThreadExecutor("worker-cleanup-thread"))
 
   // For worker and executor IDs
-  private def createDateFormat = new SimpleDateFormat("yyyyMMddHHmmss")
+  private def createDateFormat = new SimpleDateFormat("yyyyMMddHHmmss", Locale.US)
   // Send a heartbeat every (heartbeat timeout) / 4 milliseconds
   private val HEARTBEAT_MILLIS = conf.getLong("spark.worker.timeout", 60) * 1000 / 4
 
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 e1cf3938de..36a2f5c87e 100644
--- a/core/src/main/scala/org/apache/spark/rdd/HadoopRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/HadoopRDD.scala
@@ -19,7 +19,7 @@ package org.apache.spark.rdd
 
 import java.io.IOException
 import java.text.SimpleDateFormat
-import java.util.Date
+import java.util.{Date, Locale}
 
 import scala.collection.immutable.Map
 import scala.reflect.ClassTag
@@ -243,7 +243,8 @@ class HadoopRDD[K, V](
 
       var reader: RecordReader[K, V] = null
       val inputFormat = getInputFormat(jobConf)
-      HadoopRDD.addLocalConfiguration(new SimpleDateFormat("yyyyMMddHHmmss").format(createTime),
+      HadoopRDD.addLocalConfiguration(
+        new SimpleDateFormat("yyyyMMddHHmmss", Locale.US).format(createTime),
         context.stageId, theSplit.index, context.attemptNumber, jobConf)
       reader = inputFormat.getRecordReader(split.inputSplit.value, jobConf, Reporter.NULL)
 
diff --git a/core/src/main/scala/org/apache/spark/rdd/NewHadoopRDD.scala b/core/src/main/scala/org/apache/spark/rdd/NewHadoopRDD.scala
index baf31fb658..488e777fea 100644
--- a/core/src/main/scala/org/apache/spark/rdd/NewHadoopRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/NewHadoopRDD.scala
@@ -19,7 +19,7 @@ package org.apache.spark.rdd
 
 import java.io.IOException
 import java.text.SimpleDateFormat
-import java.util.Date
+import java.util.{Date, Locale}
 
 import scala.reflect.ClassTag
 
@@ -79,7 +79,7 @@ class NewHadoopRDD[K, V](
   // private val serializableConf = new SerializableWritable(_conf)
 
   private val jobTrackerId: String = {
-    val formatter = new SimpleDateFormat("yyyyMMddHHmmss")
+    val formatter = new SimpleDateFormat("yyyyMMddHHmmss", Locale.US)
     formatter.format(new Date())
   }
 
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 068f4ed8ad..67baad1c51 100644
--- a/core/src/main/scala/org/apache/spark/rdd/PairRDDFunctions.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/PairRDDFunctions.scala
@@ -19,7 +19,7 @@ package org.apache.spark.rdd
 
 import java.nio.ByteBuffer
 import java.text.SimpleDateFormat
-import java.util.{Date, HashMap => JHashMap}
+import java.util.{Date, HashMap => JHashMap, Locale}
 
 import scala.collection.{mutable, Map}
 import scala.collection.JavaConverters._
@@ -1079,7 +1079,7 @@ class PairRDDFunctions[K, V](self: RDD[(K, V)])
     // Rename this as hadoopConf internally to avoid shadowing (see SPARK-2038).
     val hadoopConf = conf
     val job = NewAPIHadoopJob.getInstance(hadoopConf)
-    val formatter = new SimpleDateFormat("yyyyMMddHHmmss")
+    val formatter = new SimpleDateFormat("yyyyMMddHHmmss", Locale.US)
     val jobtrackerID = formatter.format(new Date())
     val stageId = self.id
     val jobConfiguration = job.getConfiguration
diff --git a/core/src/main/scala/org/apache/spark/status/api/v1/JacksonMessageWriter.scala b/core/src/main/scala/org/apache/spark/status/api/v1/JacksonMessageWriter.scala
index f6a9f9c557..76af33c1a1 100644
--- a/core/src/main/scala/org/apache/spark/status/api/v1/JacksonMessageWriter.scala
+++ b/core/src/main/scala/org/apache/spark/status/api/v1/JacksonMessageWriter.scala
@@ -21,7 +21,7 @@ import java.lang.annotation.Annotation
 import java.lang.reflect.Type
 import java.nio.charset.StandardCharsets
 import java.text.SimpleDateFormat
-import java.util.{Calendar, SimpleTimeZone}
+import java.util.{Calendar, Locale, SimpleTimeZone}
 import javax.ws.rs.Produces
 import javax.ws.rs.core.{MediaType, MultivaluedMap}
 import javax.ws.rs.ext.{MessageBodyWriter, Provider}
@@ -86,7 +86,7 @@ private[v1] class JacksonMessageWriter extends MessageBodyWriter[Object]{
 
 private[spark] object JacksonMessageWriter {
   def makeISODateFormat: SimpleDateFormat = {
-    val iso8601 = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'GMT'")
+    val iso8601 = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'GMT'", Locale.US)
     val cal = Calendar.getInstance(new SimpleTimeZone(0, "GMT"))
     iso8601.setCalendar(cal)
     iso8601
diff --git a/core/src/main/scala/org/apache/spark/status/api/v1/SimpleDateParam.scala b/core/src/main/scala/org/apache/spark/status/api/v1/SimpleDateParam.scala
index 0c71cd2382..d8d5e8958b 100644
--- a/core/src/main/scala/org/apache/spark/status/api/v1/SimpleDateParam.scala
+++ b/core/src/main/scala/org/apache/spark/status/api/v1/SimpleDateParam.scala
@@ -17,7 +17,7 @@
 package org.apache.spark.status.api.v1
 
 import java.text.{ParseException, SimpleDateFormat}
-import java.util.TimeZone
+import java.util.{Locale, TimeZone}
 import javax.ws.rs.WebApplicationException
 import javax.ws.rs.core.Response
 import javax.ws.rs.core.Response.Status
@@ -25,12 +25,12 @@ import javax.ws.rs.core.Response.Status
 private[v1] class SimpleDateParam(val originalValue: String) {
 
   val timestamp: Long = {
-    val format = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSz")
+    val format = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSz", Locale.US)
     try {
       format.parse(originalValue).getTime()
     } catch {
       case _: ParseException =>
-        val gmtDay = new SimpleDateFormat("yyyy-MM-dd")
+        val gmtDay = new SimpleDateFormat("yyyy-MM-dd", Locale.US)
         gmtDay.setTimeZone(TimeZone.getTimeZone("GMT"))
         try {
           gmtDay.parse(originalValue).getTime()
diff --git a/core/src/main/scala/org/apache/spark/ui/UIUtils.scala b/core/src/main/scala/org/apache/spark/ui/UIUtils.scala
index c0d1a2220f..66b097aa81 100644
--- a/core/src/main/scala/org/apache/spark/ui/UIUtils.scala
+++ b/core/src/main/scala/org/apache/spark/ui/UIUtils.scala
@@ -36,7 +36,8 @@ private[spark] object UIUtils extends Logging {
 
   // SimpleDateFormat is not thread-safe. Don't expose it to avoid improper use.
   private val dateFormat = new ThreadLocal[SimpleDateFormat]() {
-    override def initialValue(): SimpleDateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss")
+    override def initialValue(): SimpleDateFormat =
+      new SimpleDateFormat("yyyy/MM/dd HH:mm:ss", Locale.US)
   }
 
   def formatDate(date: Date): String = dateFormat.get.format(date)
diff --git a/core/src/main/scala/org/apache/spark/util/logging/RollingPolicy.scala b/core/src/main/scala/org/apache/spark/util/logging/RollingPolicy.scala
index 5c4238c038..1f263df57c 100644
--- a/core/src/main/scala/org/apache/spark/util/logging/RollingPolicy.scala
+++ b/core/src/main/scala/org/apache/spark/util/logging/RollingPolicy.scala
@@ -18,7 +18,7 @@
 package org.apache.spark.util.logging
 
 import java.text.SimpleDateFormat
-import java.util.Calendar
+import java.util.{Calendar, Locale}
 
 import org.apache.spark.internal.Logging
 
@@ -59,7 +59,7 @@ private[spark] class TimeBasedRollingPolicy(
   }
 
   @volatile private var nextRolloverTime = calculateNextRolloverTime()
-  private val formatter = new SimpleDateFormat(rollingFileSuffixPattern)
+  private val formatter = new SimpleDateFormat(rollingFileSuffixPattern, Locale.US)
 
   /** Should rollover if current time has exceeded next rollover time */
   def shouldRollover(bytesToBeWritten: Long): Boolean = {
@@ -109,7 +109,7 @@ private[spark] class SizeBasedRollingPolicy(
   }
 
   @volatile private var bytesWrittenSinceRollover = 0L
-  val formatter = new SimpleDateFormat("--yyyy-MM-dd--HH-mm-ss--SSSS")
+  val formatter = new SimpleDateFormat("--yyyy-MM-dd--HH-mm-ss--SSSS", Locale.US)
 
   /** Should rollover if the next set of bytes is going to exceed the size limit */
   def shouldRollover(bytesToBeWritten: Long): Boolean = {
diff --git a/core/src/test/scala/org/apache/spark/util/UtilsSuite.scala b/core/src/test/scala/org/apache/spark/util/UtilsSuite.scala
index 15ef32f21d..feacfb7642 100644
--- a/core/src/test/scala/org/apache/spark/util/UtilsSuite.scala
+++ b/core/src/test/scala/org/apache/spark/util/UtilsSuite.scala
@@ -264,7 +264,7 @@ class UtilsSuite extends SparkFunSuite with ResetSystemProperties with Logging {
     val hour = minute * 60
     def str: (Long) => String = Utils.msDurationToString(_)
 
-    val sep = new DecimalFormatSymbols(Locale.getDefault()).getDecimalSeparator()
+    val sep = new DecimalFormatSymbols(Locale.US).getDecimalSeparator
 
     assert(str(123) === "123 ms")
     assert(str(second) === "1" + sep + "0 s")
diff --git a/mesos/src/main/scala/org/apache/spark/deploy/rest/mesos/MesosRestServer.scala b/mesos/src/main/scala/org/apache/spark/deploy/rest/mesos/MesosRestServer.scala
index 3b96488a12..ff60b88c6d 100644
--- a/mesos/src/main/scala/org/apache/spark/deploy/rest/mesos/MesosRestServer.scala
+++ b/mesos/src/main/scala/org/apache/spark/deploy/rest/mesos/MesosRestServer.scala
@@ -19,7 +19,7 @@ package org.apache.spark.deploy.rest.mesos
 
 import java.io.File
 import java.text.SimpleDateFormat
-import java.util.Date
+import java.util.{Date, Locale}
 import java.util.concurrent.atomic.AtomicLong
 import javax.servlet.http.HttpServletResponse
 
@@ -62,11 +62,10 @@ private[mesos] class MesosSubmitRequestServlet(
   private val DEFAULT_CORES = 1.0
 
   private val nextDriverNumber = new AtomicLong(0)
-  private def createDateFormat = new SimpleDateFormat("yyyyMMddHHmmss")  // For application IDs
-  private def newDriverId(submitDate: Date): String = {
-    "driver-%s-%04d".format(
-      createDateFormat.format(submitDate), nextDriverNumber.incrementAndGet())
-  }
+  // For application IDs
+  private def createDateFormat = new SimpleDateFormat("yyyyMMddHHmmss", Locale.US)
+  private def newDriverId(submitDate: Date): String =
+    f"driver-${createDateFormat.format(submitDate)}-${nextDriverNumber.incrementAndGet()}%04d"
 
   /**
    * Build a driver description from the fields specified in the submit request.
diff --git a/mllib/src/main/scala/org/apache/spark/mllib/pmml/export/PMMLModelExport.scala b/mllib/src/main/scala/org/apache/spark/mllib/pmml/export/PMMLModelExport.scala
index 426bb818c9..f5ca1c221d 100644
--- a/mllib/src/main/scala/org/apache/spark/mllib/pmml/export/PMMLModelExport.scala
+++ b/mllib/src/main/scala/org/apache/spark/mllib/pmml/export/PMMLModelExport.scala
@@ -18,7 +18,7 @@
 package org.apache.spark.mllib.pmml.export
 
 import java.text.SimpleDateFormat
-import java.util.Date
+import java.util.{Date, Locale}
 
 import scala.beans.BeanProperty
 
@@ -34,7 +34,7 @@ private[mllib] trait PMMLModelExport {
     val version = getClass.getPackage.getImplementationVersion
     val app = new Application("Apache Spark MLlib").setVersion(version)
     val timestamp = new Timestamp()
-      .addContent(new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss").format(new Date()))
+      .addContent(new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss", Locale.US).format(new Date()))
     val header = new Header()
       .setApplication(app)
       .setTimestamp(timestamp)
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/datetimeExpressions.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/datetimeExpressions.scala
index 7ab68a13e0..67c078ae5e 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/datetimeExpressions.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/datetimeExpressions.scala
@@ -18,7 +18,7 @@
 package org.apache.spark.sql.catalyst.expressions
 
 import java.text.SimpleDateFormat
-import java.util.{Calendar, TimeZone}
+import java.util.{Calendar, Locale, TimeZone}
 
 import scala.util.Try
 
@@ -331,7 +331,7 @@ case class DateFormatClass(left: Expression, right: Expression) extends BinaryEx
   override def inputTypes: Seq[AbstractDataType] = Seq(TimestampType, StringType)
 
   override protected def nullSafeEval(timestamp: Any, format: Any): Any = {
-    val sdf = new SimpleDateFormat(format.toString)
+    val sdf = new SimpleDateFormat(format.toString, Locale.US)
     UTF8String.fromString(sdf.format(new java.util.Date(timestamp.asInstanceOf[Long] / 1000)))
   }
 
@@ -400,7 +400,7 @@ abstract class UnixTime extends BinaryExpression with ExpectsInputTypes {
 
   private lazy val constFormat: UTF8String = right.eval().asInstanceOf[UTF8String]
   private lazy val formatter: SimpleDateFormat =
-    Try(new SimpleDateFormat(constFormat.toString)).getOrElse(null)
+    Try(new SimpleDateFormat(constFormat.toString, Locale.US)).getOrElse(null)
 
   override def eval(input: InternalRow): Any = {
     val t = left.eval(input)
@@ -425,7 +425,7 @@ abstract class UnixTime extends BinaryExpression with ExpectsInputTypes {
             null
           } else {
             val formatString = f.asInstanceOf[UTF8String].toString
-            Try(new SimpleDateFormat(formatString).parse(
+            Try(new SimpleDateFormat(formatString, Locale.US).parse(
               t.asInstanceOf[UTF8String].toString).getTime / 1000L).getOrElse(null)
           }
       }
@@ -520,7 +520,7 @@ case class FromUnixTime(sec: Expression, format: Expression)
 
   private lazy val constFormat: UTF8String = right.eval().asInstanceOf[UTF8String]
   private lazy val formatter: SimpleDateFormat =
-    Try(new SimpleDateFormat(constFormat.toString)).getOrElse(null)
+    Try(new SimpleDateFormat(constFormat.toString, Locale.US)).getOrElse(null)
 
   override def eval(input: InternalRow): Any = {
     val time = left.eval(input)
@@ -539,9 +539,10 @@ case class FromUnixTime(sec: Expression, format: Expression)
         if (f == null) {
           null
         } else {
-          Try(UTF8String.fromString(new SimpleDateFormat(
-            f.asInstanceOf[UTF8String].toString).format(new java.util.Date(
-              time.asInstanceOf[Long] * 1000L)))).getOrElse(null)
+          Try(
+            UTF8String.fromString(new SimpleDateFormat(f.toString, Locale.US).
+              format(new java.util.Date(time.asInstanceOf[Long] * 1000L)))
+          ).getOrElse(null)
         }
       }
     }
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/stringExpressions.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/stringExpressions.scala
index 1bcbb6cfc9..25a5e3fd7d 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/stringExpressions.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/stringExpressions.scala
@@ -1415,7 +1415,7 @@ case class Sentences(
       val locale = if (languageStr != null && countryStr != null) {
         new Locale(languageStr.toString, countryStr.toString)
       } else {
-        Locale.getDefault
+        Locale.US
       }
       getSentences(string.asInstanceOf[UTF8String].toString, locale)
     }
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/json/JSONOptions.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/json/JSONOptions.scala
index aec18922ea..c45970658c 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/json/JSONOptions.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/json/JSONOptions.scala
@@ -17,6 +17,8 @@
 
 package org.apache.spark.sql.catalyst.json
 
+import java.util.Locale
+
 import com.fasterxml.jackson.core.{JsonFactory, JsonParser}
 import org.apache.commons.lang3.time.FastDateFormat
 
@@ -56,11 +58,11 @@ private[sql] class JSONOptions(
 
   // Uses `FastDateFormat` which can be direct replacement for `SimpleDateFormat` and thread-safe.
   val dateFormat: FastDateFormat =
-    FastDateFormat.getInstance(parameters.getOrElse("dateFormat", "yyyy-MM-dd"))
+    FastDateFormat.getInstance(parameters.getOrElse("dateFormat", "yyyy-MM-dd"), Locale.US)
 
   val timestampFormat: FastDateFormat =
     FastDateFormat.getInstance(
-      parameters.getOrElse("timestampFormat", "yyyy-MM-dd'T'HH:mm:ss.SSSZZ"))
+      parameters.getOrElse("timestampFormat", "yyyy-MM-dd'T'HH:mm:ss.SSSZZ"), Locale.US)
 
   // Parse mode flags
   if (!ParseModes.isValidMode(parseMode)) {
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/util/DateTimeUtils.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/util/DateTimeUtils.scala
index 0b643a5b84..235ca8d263 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/util/DateTimeUtils.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/util/DateTimeUtils.scala
@@ -19,7 +19,7 @@ package org.apache.spark.sql.catalyst.util
 
 import java.sql.{Date, Timestamp}
 import java.text.{DateFormat, SimpleDateFormat}
-import java.util.{Calendar, TimeZone}
+import java.util.{Calendar, Locale, TimeZone}
 import javax.xml.bind.DatatypeConverter
 
 import scala.annotation.tailrec
@@ -79,14 +79,14 @@ object DateTimeUtils {
   // `SimpleDateFormat` is not thread-safe.
   val threadLocalTimestampFormat = new ThreadLocal[DateFormat] {
     override def initialValue(): SimpleDateFormat = {
-      new SimpleDateFormat("yyyy-MM-dd HH:mm:ss")
+      new SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.US)
     }
   }
 
   // `SimpleDateFormat` is not thread-safe.
   private val threadLocalDateFormat = new ThreadLocal[DateFormat] {
     override def initialValue(): SimpleDateFormat = {
-      new SimpleDateFormat("yyyy-MM-dd")
+      new SimpleDateFormat("yyyy-MM-dd", Locale.US)
     }
   }
 
diff --git a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/DateExpressionsSuite.scala b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/DateExpressionsSuite.scala
index 6118a34d29..35cea25ba0 100644
--- a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/DateExpressionsSuite.scala
+++ b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/DateExpressionsSuite.scala
@@ -19,7 +19,7 @@ package org.apache.spark.sql.catalyst.expressions
 
 import java.sql.{Date, Timestamp}
 import java.text.SimpleDateFormat
-import java.util.Calendar
+import java.util.{Calendar, Locale}
 
 import org.apache.spark.SparkFunSuite
 import org.apache.spark.sql.catalyst.util.DateTimeUtils
@@ -30,8 +30,8 @@ class DateExpressionsSuite extends SparkFunSuite with ExpressionEvalHelper {
 
   import IntegralLiteralTestUtils._
 
-  val sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss")
-  val sdfDate = new SimpleDateFormat("yyyy-MM-dd")
+  val sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.US)
+  val sdfDate = new SimpleDateFormat("yyyy-MM-dd", Locale.US)
   val d = new Date(sdf.parse("2015-04-08 13:10:15").getTime)
   val ts = new Timestamp(sdf.parse("2013-11-08 13:10:15").getTime)
 
@@ -49,7 +49,7 @@ class DateExpressionsSuite extends SparkFunSuite with ExpressionEvalHelper {
   }
 
   test("DayOfYear") {
-    val sdfDay = new SimpleDateFormat("D")
+    val sdfDay = new SimpleDateFormat("D", Locale.US)
     (0 to 3).foreach { m =>
       (0 to 5).foreach { i =>
         val c = Calendar.getInstance()
@@ -411,9 +411,9 @@ class DateExpressionsSuite extends SparkFunSuite with ExpressionEvalHelper {
   }
 
   test("from_unixtime") {
-    val sdf1 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss")
+    val sdf1 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.US)
     val fmt2 = "yyyy-MM-dd HH:mm:ss.SSS"
-    val sdf2 = new SimpleDateFormat(fmt2)
+    val sdf2 = new SimpleDateFormat(fmt2, Locale.US)
     checkEvaluation(
       FromUnixTime(Literal(0L), Literal("yyyy-MM-dd HH:mm:ss")), sdf1.format(new Timestamp(0)))
     checkEvaluation(FromUnixTime(
@@ -430,11 +430,11 @@ class DateExpressionsSuite extends SparkFunSuite with ExpressionEvalHelper {
   }
 
   test("unix_timestamp") {
-    val sdf1 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss")
+    val sdf1 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.US)
     val fmt2 = "yyyy-MM-dd HH:mm:ss.SSS"
-    val sdf2 = new SimpleDateFormat(fmt2)
+    val sdf2 = new SimpleDateFormat(fmt2, Locale.US)
     val fmt3 = "yy-MM-dd"
-    val sdf3 = new SimpleDateFormat(fmt3)
+    val sdf3 = new SimpleDateFormat(fmt3, Locale.US)
     val date1 = Date.valueOf("2015-07-24")
     checkEvaluation(
       UnixTimestamp(Literal(sdf1.format(new Timestamp(0))), Literal("yyyy-MM-dd HH:mm:ss")), 0L)
@@ -466,11 +466,11 @@ class DateExpressionsSuite extends SparkFunSuite with ExpressionEvalHelper {
   }
 
   test("to_unix_timestamp") {
-    val sdf1 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss")
+    val sdf1 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.US)
     val fmt2 = "yyyy-MM-dd HH:mm:ss.SSS"
-    val sdf2 = new SimpleDateFormat(fmt2)
+    val sdf2 = new SimpleDateFormat(fmt2, Locale.US)
     val fmt3 = "yy-MM-dd"
-    val sdf3 = new SimpleDateFormat(fmt3)
+    val sdf3 = new SimpleDateFormat(fmt3, Locale.US)
     val date1 = Date.valueOf("2015-07-24")
     checkEvaluation(
       ToUnixTimestamp(Literal(sdf1.format(new Timestamp(0))), Literal("yyyy-MM-dd HH:mm:ss")), 0L)
diff --git a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/util/DateTimeUtilsSuite.scala b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/util/DateTimeUtilsSuite.scala
index 4f516d0064..e0a9a0c3d5 100644
--- a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/util/DateTimeUtilsSuite.scala
+++ b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/util/DateTimeUtilsSuite.scala
@@ -19,7 +19,7 @@ package org.apache.spark.sql.catalyst.util
 
 import java.sql.{Date, Timestamp}
 import java.text.SimpleDateFormat
-import java.util.{Calendar, TimeZone}
+import java.util.{Calendar, Locale, TimeZone}
 
 import org.apache.spark.SparkFunSuite
 import org.apache.spark.sql.catalyst.util.DateTimeUtils._
@@ -68,8 +68,8 @@ class DateTimeUtilsSuite extends SparkFunSuite {
       assert(d2.toString === d1.toString)
     }
 
-    val df1 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss")
-    val df2 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss z")
+    val df1 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.US)
+    val df2 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss z", Locale.US)
 
     checkFromToJavaDate(new Date(100))
 
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/csv/CSVInferSchema.scala b/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/csv/CSVInferSchema.scala
index 3ab775c909..1981d8607c 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/csv/CSVInferSchema.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/csv/CSVInferSchema.scala
@@ -247,7 +247,7 @@ private[csv] object CSVTypeCast {
             case options.positiveInf => Float.PositiveInfinity
             case _ =>
               Try(datum.toFloat)
-                .getOrElse(NumberFormat.getInstance(Locale.getDefault).parse(datum).floatValue())
+                .getOrElse(NumberFormat.getInstance(Locale.US).parse(datum).floatValue())
           }
         case _: DoubleType =>
           datum match {
@@ -256,7 +256,7 @@ private[csv] object CSVTypeCast {
             case options.positiveInf => Double.PositiveInfinity
             case _ =>
               Try(datum.toDouble)
-                .getOrElse(NumberFormat.getInstance(Locale.getDefault).parse(datum).doubleValue())
+                .getOrElse(NumberFormat.getInstance(Locale.US).parse(datum).doubleValue())
           }
         case _: BooleanType => datum.toBoolean
         case dt: DecimalType =>
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/csv/CSVOptions.scala b/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/csv/CSVOptions.scala
index 014614eb99..5903729c11 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/csv/CSVOptions.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/csv/CSVOptions.scala
@@ -18,6 +18,7 @@
 package org.apache.spark.sql.execution.datasources.csv
 
 import java.nio.charset.StandardCharsets
+import java.util.Locale
 
 import org.apache.commons.lang3.time.FastDateFormat
 
@@ -104,11 +105,11 @@ private[csv] class CSVOptions(@transient private val parameters: Map[String, Str
 
   // Uses `FastDateFormat` which can be direct replacement for `SimpleDateFormat` and thread-safe.
   val dateFormat: FastDateFormat =
-    FastDateFormat.getInstance(parameters.getOrElse("dateFormat", "yyyy-MM-dd"))
+    FastDateFormat.getInstance(parameters.getOrElse("dateFormat", "yyyy-MM-dd"), Locale.US)
 
   val timestampFormat: FastDateFormat =
     FastDateFormat.getInstance(
-      parameters.getOrElse("timestampFormat", "yyyy-MM-dd'T'HH:mm:ss.SSSZZ"))
+      parameters.getOrElse("timestampFormat", "yyyy-MM-dd'T'HH:mm:ss.SSSZZ"), Locale.US)
 
   val maxColumns = getInt("maxColumns", 20480)
 
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/execution/metric/SQLMetrics.scala b/sql/core/src/main/scala/org/apache/spark/sql/execution/metric/SQLMetrics.scala
index 0cc1edd196..dbc27d8b23 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/execution/metric/SQLMetrics.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/execution/metric/SQLMetrics.scala
@@ -102,7 +102,7 @@ object SQLMetrics {
    */
   def stringValue(metricsType: String, values: Seq[Long]): String = {
     if (metricsType == SUM_METRIC) {
-      val numberFormat = NumberFormat.getIntegerInstance(Locale.ENGLISH)
+      val numberFormat = NumberFormat.getIntegerInstance(Locale.US)
       numberFormat.format(values.sum)
     } else {
       val strFormat: Long => String = if (metricsType == SIZE_METRIC) {
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/socket.scala b/sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/socket.scala
index c662e7c6bc..042977f870 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/socket.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/socket.scala
@@ -21,7 +21,7 @@ import java.io.{BufferedReader, InputStreamReader, IOException}
 import java.net.Socket
 import java.sql.Timestamp
 import java.text.SimpleDateFormat
-import java.util.Calendar
+import java.util.{Calendar, Locale}
 import javax.annotation.concurrent.GuardedBy
 
 import scala.collection.mutable.ListBuffer
@@ -37,7 +37,7 @@ object TextSocketSource {
   val SCHEMA_REGULAR = StructType(StructField("value", StringType) :: Nil)
   val SCHEMA_TIMESTAMP = StructType(StructField("value", StringType) ::
     StructField("timestamp", TimestampType) :: Nil)
-  val DATE_FORMAT = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss")
+  val DATE_FORMAT = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.US)
 }
 
 /**
diff --git a/sql/core/src/test/scala/org/apache/spark/sql/DateFunctionsSuite.scala b/sql/core/src/test/scala/org/apache/spark/sql/DateFunctionsSuite.scala
index f7aa3b747a..e05b2252ee 100644
--- a/sql/core/src/test/scala/org/apache/spark/sql/DateFunctionsSuite.scala
+++ b/sql/core/src/test/scala/org/apache/spark/sql/DateFunctionsSuite.scala
@@ -19,6 +19,7 @@ package org.apache.spark.sql
 
 import java.sql.{Date, Timestamp}
 import java.text.SimpleDateFormat
+import java.util.Locale
 
 import org.apache.spark.sql.catalyst.util.DateTimeUtils
 import org.apache.spark.sql.functions._
@@ -55,8 +56,8 @@ class DateFunctionsSuite extends QueryTest with SharedSQLContext {
     checkAnswer(sql("""SELECT CURRENT_TIMESTAMP() = NOW()"""), Row(true))
   }
 
-  val sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss")
-  val sdfDate = new SimpleDateFormat("yyyy-MM-dd")
+  val sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.US)
+  val sdfDate = new SimpleDateFormat("yyyy-MM-dd", Locale.US)
   val d = new Date(sdf.parse("2015-04-08 13:10:15").getTime)
   val ts = new Timestamp(sdf.parse("2013-04-08 13:10:15").getTime)
 
@@ -395,11 +396,11 @@ class DateFunctionsSuite extends QueryTest with SharedSQLContext {
   }
 
   test("from_unixtime") {
-    val sdf1 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss")
+    val sdf1 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.US)
     val fmt2 = "yyyy-MM-dd HH:mm:ss.SSS"
-    val sdf2 = new SimpleDateFormat(fmt2)
+    val sdf2 = new SimpleDateFormat(fmt2, Locale.US)
     val fmt3 = "yy-MM-dd HH-mm-ss"
-    val sdf3 = new SimpleDateFormat(fmt3)
+    val sdf3 = new SimpleDateFormat(fmt3, Locale.US)
     val df = Seq((1000, "yyyy-MM-dd HH:mm:ss.SSS"), (-1000, "yy-MM-dd HH-mm-ss")).toDF("a", "b")
     checkAnswer(
       df.select(from_unixtime(col("a"))),
diff --git a/sql/core/src/test/scala/org/apache/spark/sql/execution/datasources/csv/CSVSuite.scala b/sql/core/src/test/scala/org/apache/spark/sql/execution/datasources/csv/CSVSuite.scala
index f7c22c6c93..8209b5bd7f 100644
--- a/sql/core/src/test/scala/org/apache/spark/sql/execution/datasources/csv/CSVSuite.scala
+++ b/sql/core/src/test/scala/org/apache/spark/sql/execution/datasources/csv/CSVSuite.scala
@@ -21,6 +21,7 @@ import java.io.File
 import java.nio.charset.UnsupportedCharsetException
 import java.sql.{Date, Timestamp}
 import java.text.SimpleDateFormat
+import java.util.Locale
 
 import org.apache.commons.lang3.time.FastDateFormat
 import org.apache.hadoop.io.SequenceFile.CompressionType
@@ -487,7 +488,7 @@ class CSVSuite extends QueryTest with SharedSQLContext with SQLTestUtils {
       .select("date")
       .collect()
 
-    val dateFormat = new SimpleDateFormat("dd/MM/yyyy HH:mm")
+    val dateFormat = new SimpleDateFormat("dd/MM/yyyy HH:mm", Locale.US)
     val expected =
       Seq(Seq(new Timestamp(dateFormat.parse("26/08/2015 18:00").getTime)),
         Seq(new Timestamp(dateFormat.parse("27/10/2014 18:30").getTime)),
@@ -509,7 +510,7 @@ class CSVSuite extends QueryTest with SharedSQLContext with SQLTestUtils {
       .select("date")
       .collect()
 
-    val dateFormat = new SimpleDateFormat("dd/MM/yyyy hh:mm")
+    val dateFormat = new SimpleDateFormat("dd/MM/yyyy hh:mm", Locale.US)
     val expected = Seq(
       new Date(dateFormat.parse("26/08/2015 18:00").getTime),
       new Date(dateFormat.parse("27/10/2014 18:30").getTime),
@@ -728,7 +729,7 @@ class CSVSuite extends QueryTest with SharedSQLContext with SQLTestUtils {
         .option("inferSchema", "false")
         .load(iso8601timestampsPath)
 
-      val iso8501 = FastDateFormat.getInstance("yyyy-MM-dd'T'HH:mm:ss.SSSZZ")
+      val iso8501 = FastDateFormat.getInstance("yyyy-MM-dd'T'HH:mm:ss.SSSZZ", Locale.US)
       val expectedTimestamps = timestamps.collect().map { r =>
         // This should be ISO8601 formatted string.
         Row(iso8501.format(r.toSeq.head))
@@ -761,7 +762,7 @@ class CSVSuite extends QueryTest with SharedSQLContext with SQLTestUtils {
         .option("inferSchema", "false")
         .load(iso8601datesPath)
 
-      val iso8501 = FastDateFormat.getInstance("yyyy-MM-dd")
+      val iso8501 = FastDateFormat.getInstance("yyyy-MM-dd", Locale.US)
       val expectedDates = dates.collect().map { r =>
         // This should be ISO8601 formatted string.
         Row(iso8501.format(r.toSeq.head))
diff --git a/sql/core/src/test/scala/org/apache/spark/sql/execution/datasources/csv/CSVTypeCastSuite.scala b/sql/core/src/test/scala/org/apache/spark/sql/execution/datasources/csv/CSVTypeCastSuite.scala
index 51832a13cf..c74406b9cb 100644
--- a/sql/core/src/test/scala/org/apache/spark/sql/execution/datasources/csv/CSVTypeCastSuite.scala
+++ b/sql/core/src/test/scala/org/apache/spark/sql/execution/datasources/csv/CSVTypeCastSuite.scala
@@ -144,13 +144,12 @@ class CSVTypeCastSuite extends SparkFunSuite {
       DateTimeUtils.millisToDays(DateTimeUtils.stringToTime("2015-01-01").getTime))
   }
 
-  test("Float and Double Types are cast correctly with Locale") {
+  test("Float and Double Types are cast without respect to platform default Locale") {
     val originalLocale = Locale.getDefault
     try {
-      val locale : Locale = new Locale("fr", "FR")
-      Locale.setDefault(locale)
-      assert(CSVTypeCast.castTo("1,00", FloatType) == 1.0)
-      assert(CSVTypeCast.castTo("1,00", DoubleType) == 1.0)
+      Locale.setDefault(new Locale("fr", "FR"))
+      assert(CSVTypeCast.castTo("1,00", FloatType) == 100.0) // Would parse as 1.0 in fr-FR
+      assert(CSVTypeCast.castTo("1,00", DoubleType) == 100.0)
     } finally {
       Locale.setDefault(originalLocale)
     }
diff --git a/sql/hive/src/main/scala/org/apache/spark/sql/hive/execution/InsertIntoHiveTable.scala b/sql/hive/src/main/scala/org/apache/spark/sql/hive/execution/InsertIntoHiveTable.scala
index 2843100fb3..05164d774c 100644
--- a/sql/hive/src/main/scala/org/apache/spark/sql/hive/execution/InsertIntoHiveTable.scala
+++ b/sql/hive/src/main/scala/org/apache/spark/sql/hive/execution/InsertIntoHiveTable.scala
@@ -20,9 +20,7 @@ package org.apache.spark.sql.hive.execution
 import java.io.IOException
 import java.net.URI
 import java.text.SimpleDateFormat
-import java.util.{Date, Random}
-
-import scala.collection.JavaConverters._
+import java.util.{Date, Locale, Random}
 
 import org.apache.hadoop.conf.Configuration
 import org.apache.hadoop.fs.{FileSystem, Path}
@@ -60,9 +58,8 @@ case class InsertIntoHiveTable(
 
   private def executionId: String = {
     val rand: Random = new Random
-    val format: SimpleDateFormat = new SimpleDateFormat("yyyy-MM-dd_HH-mm-ss_SSS")
-    val executionId: String = "hive_" + format.format(new Date) + "_" + Math.abs(rand.nextLong)
-    return executionId
+    val format = new SimpleDateFormat("yyyy-MM-dd_HH-mm-ss_SSS", Locale.US)
+    "hive_" + format.format(new Date) + "_" + Math.abs(rand.nextLong)
   }
 
   private def getStagingDir(inputPath: Path, hadoopConf: Configuration): Path = {
diff --git a/sql/hive/src/main/scala/org/apache/spark/sql/hive/hiveWriterContainers.scala b/sql/hive/src/main/scala/org/apache/spark/sql/hive/hiveWriterContainers.scala
index ea88276bb9..e53c3e4d48 100644
--- a/sql/hive/src/main/scala/org/apache/spark/sql/hive/hiveWriterContainers.scala
+++ b/sql/hive/src/main/scala/org/apache/spark/sql/hive/hiveWriterContainers.scala
@@ -18,7 +18,7 @@
 package org.apache.spark.sql.hive
 
 import java.text.NumberFormat
-import java.util.Date
+import java.util.{Date, Locale}
 
 import scala.collection.JavaConverters._
 
@@ -95,7 +95,7 @@ private[hive] class SparkHiveWriterContainer(
   }
 
   protected def getOutputName: String = {
-    val numberFormat = NumberFormat.getInstance()
+    val numberFormat = NumberFormat.getInstance(Locale.US)
     numberFormat.setMinimumIntegerDigits(5)
     numberFormat.setGroupingUsed(false)
     val extension = Utilities.getFileExtension(conf.value, fileSinkConf.getCompressed, outputFormat)
diff --git a/sql/hive/src/test/scala/org/apache/spark/sql/sources/SimpleTextRelation.scala b/sql/hive/src/test/scala/org/apache/spark/sql/sources/SimpleTextRelation.scala
index 64d0ecbeef..cecfd99098 100644
--- a/sql/hive/src/test/scala/org/apache/spark/sql/sources/SimpleTextRelation.scala
+++ b/sql/hive/src/test/scala/org/apache/spark/sql/sources/SimpleTextRelation.scala
@@ -18,6 +18,7 @@
 package org.apache.spark.sql.sources
 
 import java.text.NumberFormat
+import java.util.Locale
 
 import org.apache.hadoop.conf.Configuration
 import org.apache.hadoop.fs.{FileStatus, Path}
@@ -141,7 +142,7 @@ class SimpleTextOutputWriter(path: String, context: TaskAttemptContext)
 
 class AppendingTextOutputFormat(path: String) extends TextOutputFormat[NullWritable, Text] {
 
-  val numberFormat = NumberFormat.getInstance()
+  val numberFormat = NumberFormat.getInstance(Locale.US)
   numberFormat.setMinimumIntegerDigits(5)
   numberFormat.setGroupingUsed(false)
 
diff --git a/streaming/src/main/scala/org/apache/spark/streaming/ui/UIUtils.scala b/streaming/src/main/scala/org/apache/spark/streaming/ui/UIUtils.scala
index 9b1c939e93..84ecf81abf 100644
--- a/streaming/src/main/scala/org/apache/spark/streaming/ui/UIUtils.scala
+++ b/streaming/src/main/scala/org/apache/spark/streaming/ui/UIUtils.scala
@@ -18,7 +18,7 @@
 package org.apache.spark.streaming.ui
 
 import java.text.SimpleDateFormat
-import java.util.TimeZone
+import java.util.{Locale, TimeZone}
 import java.util.concurrent.TimeUnit
 
 import scala.xml.Node
@@ -80,11 +80,13 @@ private[streaming] object UIUtils {
 
   // SimpleDateFormat is not thread-safe. Don't expose it to avoid improper use.
   private val batchTimeFormat = new ThreadLocal[SimpleDateFormat]() {
-    override def initialValue(): SimpleDateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss")
+    override def initialValue(): SimpleDateFormat =
+      new SimpleDateFormat("yyyy/MM/dd HH:mm:ss", Locale.US)
   }
 
   private val batchTimeFormatWithMilliseconds = new ThreadLocal[SimpleDateFormat]() {
-    override def initialValue(): SimpleDateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss.SSS")
+    override def initialValue(): SimpleDateFormat =
+      new SimpleDateFormat("yyyy/MM/dd HH:mm:ss.SSS", Locale.US)
   }
 
   /**