[SPARK-26081][SQL][FOLLOW-UP] Use foreach instead of misuse of map (f…

…or Unit)

## What changes were proposed in this pull request?

This PR proposes to use foreach instead of misuse of map (for Unit). This could cause some weird errors potentially and it's not a good practice anyway. See also SPARK-16694

## How was this patch tested?

N/A

Closes apache#23341 from HyukjinKwon/followup-SPARK-26081.

Authored-by: Hyukjin Kwon <[email protected]>
Signed-off-by: Hyukjin Kwon <[email protected]>

sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/csv/CSVFileFormat.scala

@@ -189,5 +189,5 @@ private[csv] class CsvOutputWriter(
     gen.write(row)
   }
 
-  override def close(): Unit = univocityGenerator.map(_.close())
+  override def close(): Unit = univocityGenerator.foreach(_.close())
 }

sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/json/JsonFileFormat.scala

@@ -190,5 +190,5 @@ private[json] class JsonOutputWriter(
     gen.writeLineEnding()
   }
 
-  override def close(): Unit = jacksonGenerator.map(_.close())
+  override def close(): Unit = jacksonGenerator.foreach(_.close())
 }

sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/text/TextFileFormat.scala

@@ -153,7 +153,7 @@ class TextOutputWriter(
   private var outputStream: Option[OutputStream] = None
 
   override def write(row: InternalRow): Unit = {
-    val os = outputStream.getOrElse{
+    val os = outputStream.getOrElse {
       val newStream = CodecStreams.createOutputStream(context, new Path(path))
       outputStream = Some(newStream)
       newStream
@@ -167,6 +167,6 @@ class TextOutputWriter(
   }
 
   override def close(): Unit = {
-    outputStream.map(_.close())
+    outputStream.foreach(_.close())
   }
 }