Convert List to JSON (#14226)

Hello there, 
The code provides a test class for a Java list to JSON conversion.
Regards,
Mohamed.

core-java-modules/core-java-collections-list-5/src/test/java/com/baeldung/listtojson/ListToJsonArrayUnitTest.java

@@ -0,0 +1,35 @@
+package com.baeldung.listtojson;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.google.gson.Gson;
+import org.json.JSONArray;
+import org.junit.Assert;
+import java.util.Arrays;
+import org.junit.Test;
+import java.util.List;
+
+public class ListToJsonArrayUnitTest {
+    public List<String> list = Arrays.asList("Article 1", "Article 2", "Article 3");
+    public String expectedJsonArray = "[\"Article 1\",\"Article 2\",\"Article 3\"]";
+
+@Test
+public void given_JavaList_whenUsingJacksonLibrary_thenOutJsonArray() throws JsonProcessingException {
+    ObjectMapper objectMapper = new ObjectMapper();
+    String jsonArray = objectMapper.writeValueAsString(list);
+    Assert.assertEquals(expectedJsonArray, jsonArray);
+}
+
+    @Test
+    public void given_JavaList_whenUsingGsonLibrary_thenOutJsonArray() {
+        Gson gson = new Gson();
+        String jsonArray = gson.toJson(list);
+        Assert.assertEquals(expectedJsonArray, jsonArray);
+    }
+
+    @Test
+    public void given_JavaList_whenOrgJsonLibrary_thenOutJsonAray() {
+        JSONArray jsonArray = new JSONArray(list);
+        Assert.assertEquals(expectedJsonArray, jsonArray.toString());
+    }
+
+}