Update Cast.scala

Author: baishuo

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/Cast.scala

@@ -18,10 +18,9 @@
 package org.apache.spark.sql.catalyst.expressions
 
 import java.sql.Timestamp
-import java.text.{DateFormat, NumberFormat, SimpleDateFormat}
+import java.text.{DateFormat, SimpleDateFormat}
 
 import org.apache.spark.sql.catalyst.types._
-import java.util.Locale
 
 /** Cast the child expression to the target data type. */
 case class Cast(child: Expression, dataType: DataType) extends UnaryExpression {
@@ -272,9 +271,4 @@ object Cast {
       new SimpleDateFormat("yyyy-MM-dd HH:mm:ss")
     }
   }
-  private[sql] val threadLocalNumberFormat = new ThreadLocal[NumberFormat] {
-    override def initialValue() = {
-      NumberFormat.getInstance()
-    }
-  }
 }