spot bugs

sdk/core/azure-core/src/main/java/com/azure/core/util/logging/LoggingEventBuilder.java

@@ -369,11 +369,11 @@ private void performLogging(LogLevel logLevel, String format, Object... args) {
      * Serializes passed map to string containing valid JSON fragment:
      * e.g. "k1":"v1","k2":"v2", properly escaped and without trailing comma.
      *
-     * Does not support custom or complex object serialization, uses {@code toString()} on them.
+     * For complex object serialization, it calls {@code toString()} guarded with null check.
      *
      * @param context to serialize.
      *
-     * @returns Serialized JSON fragment or empty string.
+     * @returns Serialized JSON fragment or an empty string.
      */
     static String writeJsonFragment(Map<String, Object> context) {
         if (CoreUtils.isNullOrEmpty(context)) {
@@ -399,20 +399,36 @@ private static StringBuilder writeKeyAndValue(String key, Object value, StringBu
             return formatter.append("null");
         }
 
-        // LoggingEventBuilder only populates primitives and Strings
-        if (value instanceof Boolean
-            || value instanceof Integer
-            || value instanceof Long
-            || value instanceof Byte) {
-                JSON_STRING_ENCODER.quoteAsString(value.toString(), formatter);
-                return formatter;
+        if (isPrimitive(value)) {
+            JSON_STRING_ENCODER.quoteAsString(value.toString(), formatter);
+            return formatter;
         }
 
         formatter.append("\"");
         JSON_STRING_ENCODER.quoteAsString(value.toString(), formatter);
         return formatter.append("\"");
     }
 
+    /**
+     *  Returns true if the value is an instance of a primitive type and false otherwise.
+     */
+    private static boolean isPrimitive(Object value) {
+        // most of the time values are strings
+        if (value instanceof String) {
+            return false;
+        }
+
+        if (value instanceof Boolean
+            || value instanceof Integer
+            || value instanceof Long
+            || value instanceof Byte
+            || value instanceof Double
+            || value instanceof Float) {
+            return true;
+        }
+
+        return false;
+    }
 
     private static final class ContextKeyValuePair {
         private final String key;