BAEL-2499 Write to CSV in Java - updated (#6135)

* example code for Article How to Write to a CSV File in Java

* Updated to use a Stream

* Updated to use Streams in convertToCSV for BAEL-2499

core-java-io/src/main/java/com/baeldung/csv/WriteCsvFileExample.java

@@ -1,18 +1,14 @@
 package com.baeldung.csv;
 
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
 public class WriteCsvFileExample {
 
     public String convertToCSV(String[] data) {
-        StringBuilder csvLine = new StringBuilder();
-
-        for (int i = 0; i < data.length; i++) {
-            if (i > 0) {
-                csvLine.append(",");
-            }
-            csvLine.append(escapeSpecialCharacters(data[i]));
-        }
-
-        return csvLine.toString();
+        return Stream.of(data)
+            .map(this::escapeSpecialCharacters)
+            .collect(Collectors.joining(","));
     }
 
     public String escapeSpecialCharacters(String data) {

core-java-io/src/test/java/com/baeldung/csv/WriteCsvFileExampleUnitTest.java

@@ -65,7 +65,7 @@ public class WriteCsvFileExampleUnitTest {
     }
 
     @Test
-    public void givenBufferedWriter_whenWriteLine_thenOutputCreated() {
+    public void givenDataArray_whenConvertToCSV_thenOutputCreated() {
         List<String[]> dataLines = new ArrayList<String[]>();
         dataLines.add(new String[] { "John", "Doe", "38", "Comment Data\nAnother line of comment data" });
         dataLines.add(new String[] { "Jane", "Doe, Jr.", "19", "She said \"I'm being quoted\"" });