diff --git a/flint-core/src/main/java/org/opensearch/flint/core/logging/CustomJsonLayout.java b/flint-core/src/main/java/org/opensearch/flint/core/logging/CustomJsonLayout.java
index 98715c2c2..a719e5faa 100644
--- a/flint-core/src/main/java/org/opensearch/flint/core/logging/CustomJsonLayout.java
+++ b/flint-core/src/main/java/org/opensearch/flint/core/logging/CustomJsonLayout.java
@@ -18,6 +18,13 @@
 import java.util.HashMap;
 import java.util.Map;
 
+/**
+ * CustomJsonLayout is a plugin for formatting log events as JSON strings.
+ *
+ * <p>The layout is designed to be used with OpenSearch Flint logging. It extracts environment-specific information,
+ * such as the cluster name, from the environment variable "FLINT_CLUSTER_NAME" and splits it into domain name and client ID.</p>
+ *
+ */
 @Plugin(name = "CustomJsonLayout", category = "Core", elementType = Layout.ELEMENT_TYPE, printObject = true)
 public class CustomJsonLayout extends AbstractStringLayout {
     private static final ObjectMapper OBJECT_MAPPER = new ObjectMapper();
@@ -41,17 +48,26 @@ protected CustomJsonLayout(Charset charset) {
         super(charset);
     }
 
+    /**
+     * Plugin factory method to create an instance of CustomJsonLayout.
+     *
+     * @param charset The charset for encoding the log event. If not specified, defaults to UTF-8.
+     * @return A new instance of CustomJsonLayout with the specified charset.
+     */
     @PluginFactory
     public static CustomJsonLayout createLayout(@PluginAttribute(value = "charset", defaultString = "UTF-8")  Charset charset) {
         return new CustomJsonLayout(charset);
     }
 
+    /**
+     * Converts the log event to a JSON string.
+     * If the log event's message does not follow the expected format, it returns the formatted message directly.
+     *
+     * @param event the log event to format.
+     * @return A string representation of the log event in JSON format.
+     */
     @Override
     public String toSerializable(LogEvent event) {
-        if (!(event.getMessage() instanceof OperationMessage)) {
-            return event.getMessage().getFormattedMessage() + System.lineSeparator();
-        }
-
         Map<String, Object> logEventMap = new HashMap<>();
         logEventMap.put("timestamp", event.getTimeMillis());
         logEventMap.put("message", event.getMessage().getFormattedMessage());
diff --git a/flint-core/src/main/java/org/opensearch/flint/core/logging/CustomLogging.java b/flint-core/src/main/java/org/opensearch/flint/core/logging/CustomLogging.java
new file mode 100644
index 000000000..de3879b1d
--- /dev/null
+++ b/flint-core/src/main/java/org/opensearch/flint/core/logging/CustomLogging.java
@@ -0,0 +1,36 @@
+package org.opensearch.flint.core.logging;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+/**
+ * CustomLogging class using the {@link CustomJsonLayout} for logging.
+ */
+public class CustomLogging {
+    // Define a static logger variable so that it references the custom logger
+    private static final Logger logger = LogManager.getLogger(CustomLogging.class);
+
+    public static void logDebug(String message) {
+        logger.debug(message);
+    }
+
+    public static void logInfo(String message) {
+        logger.info(message);
+    }
+
+    public static void logWarning(String message) {
+        logger.warn(message);
+    }
+
+    public static void logWarning(String message, Throwable e) {
+        logger.warn(message, e);
+    }
+
+    public static void logError(String message) {
+        logger.error(message);
+    }
+
+    public static void logError(String message, Throwable throwable) {
+        logger.error(message, throwable);
+    }
+}
\ No newline at end of file
diff --git a/flint-core/src/main/scala/org/opensearch/flint/core/http/handler/HttpStatusCodeResultPredicate.java b/flint-core/src/main/scala/org/opensearch/flint/core/http/handler/HttpStatusCodeResultPredicate.java
index ee2a23e3f..fa82e3655 100644
--- a/flint-core/src/main/scala/org/opensearch/flint/core/http/handler/HttpStatusCodeResultPredicate.java
+++ b/flint-core/src/main/scala/org/opensearch/flint/core/http/handler/HttpStatusCodeResultPredicate.java
@@ -18,6 +18,7 @@
  * @param <T> result type (supposed to be HttpResponse for OS client)
  */
 public class HttpStatusCodeResultPredicate<T> implements CheckedPredicate<T> {
+
   private static final Logger LOG = Logger.getLogger(HttpStatusCodeResultPredicate.class.getName());
 
   /**
diff --git a/flint-core/src/test/java/org/opensearch/flint/core/logging/CustomJsonLayoutTest.java b/flint-core/src/test/java/org/opensearch/flint/core/logging/CustomJsonLayoutTest.java
index 271f00a06..95dbe2fb3 100644
--- a/flint-core/src/test/java/org/opensearch/flint/core/logging/CustomJsonLayoutTest.java
+++ b/flint-core/src/test/java/org/opensearch/flint/core/logging/CustomJsonLayoutTest.java
@@ -21,18 +21,6 @@
 
 
 public class CustomJsonLayoutTest {
-    @Test
-    public void testSuccessfulLogPlainMessage() {
-        LogEvent event = mock(LogEvent.class);
-        when(event.getMessage()).thenReturn(mock(Message.class));
-        when(event.getMessage().getFormattedMessage()).thenReturn("Test message");
-
-        CustomJsonLayout layout = CustomJsonLayout.createLayout(StandardCharsets.UTF_8);
-        String result = layout.toSerializable(event);
-        assertNotNull(result);
-        assertEquals(result, "Test message" + System.lineSeparator());
-    }
-
     @Test
     public void testSuccessfulLogOperationMessage() throws NoSuchFieldException, IllegalAccessException {
         Class<?> classOfMap = System.getenv().getClass();
@@ -47,6 +35,9 @@ public void testSuccessfulLogOperationMessage() throws NoSuchFieldException, Ill
         when(event.getMessage().getFormattedMessage()).thenReturn("Test message");
         when(event.getMessage().getParameters()).thenReturn(new Object[] {new Integer(200)});
 
+        Exception mockException = new Exception("Test exception message");
+        when(event.getThrown()).thenReturn(mockException);
+
         try {
             CustomJsonLayout layout = CustomJsonLayout.createLayout(StandardCharsets.UTF_8);
 
@@ -56,6 +47,8 @@ public void testSuccessfulLogOperationMessage() throws NoSuchFieldException, Ill
             assertTrue(result.contains("\"clientId\":\"1234567890\""));
             assertTrue(result.contains("\"domainName\":\"testDomain\""));
             assertTrue(result.contains("\"StatusCode\":200"));
+            assertTrue(result.contains("\"Exception\":\"java.lang.Exception\""));
+            assertTrue(result.contains("\"ExceptionMessage\":\"Test exception message\""));
         } finally {
             // since system environment is shared by other tests. Make sure to remove them before exiting.
             writeableEnvironmentVariables.remove("FLINT_CLUSTER_NAME");