[BAEL-6393] Add support for JsonNode to ArrayNode conversion (#15963)

Co-authored-by: rajatgarg <rajatgarg@adobe.com>

json-modules/json-conversion/src/test/java/com/baeldung/jsonnodetoarraynode/JsonNodeToArrayNodeConverterUnitTest.java

@@ -0,0 +1,73 @@
+package com.baeldung.jsonnodetoarraynode;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.Iterator;
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.StreamSupport;
+
+import org.junit.jupiter.api.Test;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.node.ArrayNode;
+
+public class JsonNodeToArrayNodeConverterUnitTest {
+    @Test
+    void givenJsonNode_whenUsingJsonNodeMethods_thenConvertToArrayNode() throws JsonProcessingException {
+        int count = 0;
+        String json = "{\"objects\": [\"One\", \"Two\", \"Three\"]}";
+        final JsonNode arrayNode = new ObjectMapper().readTree(json).get("objects");
+        if (arrayNode.isArray()) {
+            for (final JsonNode objNode : arrayNode) {
+                assertNotNull(objNode, "Array element should not be null");
+                count++;
+            }
+        }
+        assertNotNull(arrayNode, "The 'objects' array should not be null");
+        assertTrue(arrayNode.isArray(), "The 'objects' should be an array");
+        assertEquals(3, count, "The 'objects' array should have 3 elements");
+    }
+
+     @Test
+     void givenJsonNode_whenUsingCreateArrayNode_thenConvertToArrayNode() throws Exception {
+        ObjectMapper objectMapper = new ObjectMapper();
+        JsonNode originalJsonNode = objectMapper.readTree("{\"objects\": [\"One\", \"Two\", \"Three\"]}");
+        ArrayNode arrayNode = objectMapper.createArrayNode();
+        originalJsonNode.get("objects").elements().forEachRemaining(arrayNode::add);
+        assertEquals("[\"One\",\"Two\",\"Three\"]", arrayNode.toString());
+    }
+
+    @Test
+     void givenJsonNode_whenUsingStreamSupport_thenConvertToArrayNode() throws Exception {
+        String json = "{\"objects\": [\"One\", \"Two\", \"Three\"]}";
+        JsonNode obj = new ObjectMapper().readTree(json);
+        List<JsonNode> objects = StreamSupport
+            .stream(obj.get("objects").spliterator(), false)
+            .collect(Collectors.toList());
+
+        assertEquals(3, objects.size(), "The 'objects' list should contain 3 elements");
+
+        JsonNode firstObject = objects.get(0);
+        assertEquals("One", firstObject.asText(), "The first element should be One");
+    }
+
+    @Test
+     void givenJsonNode_whenUsingIterator_thenConvertToArrayNode() throws Exception {
+        String json = "{\"objects\": [\"One\", \"Two\", \"Three\"]}";
+        JsonNode datasets = new ObjectMapper().readTree(json);
+        Iterator<JsonNode> iterator = datasets.withArray("objects").elements();
+
+        int count = 0;
+        while (iterator.hasNext()) {
+            JsonNode dataset = iterator.next();
+            System.out.print(dataset.toString() + " ");
+            count++;
+        }
+        assertEquals(3, count, "The 'objects' list should contain 3 elements");
+    }
+}