comments.:

Author: zhumin8

oauth2_http/java/com/google/auth/oauth2/Slf4jLoggingHelpers.java

@@ -109,6 +109,7 @@ static void logRequest(HttpRequest request, LoggerProvider loggerProvider, Strin
     }
   }
 
+  /** Logs response status code, status.message, and headers */
   static void logResponse(HttpResponse response, LoggerProvider loggerProvider, String message) {
     try {
       Logger logger = loggerProvider.getLogger();
@@ -126,6 +127,7 @@ static void logResponse(HttpResponse response, LoggerProvider loggerProvider, St
     }
   }
 
+  /** Logs parsed response payload */
   static void logResponsePayload(
       GenericData genericData, LoggerProvider loggerProvider, String message) {
     try {
@@ -155,6 +157,7 @@ private static Map<String, Object> parseGenericData(GenericData genericData) {
     return contextMap;
   }
 
+  // calculate SHA256Hash so we do not print secrets directly to log
   private static String calculateSHA256Hash(String data) {
     try {
       MessageDigest digest = MessageDigest.getInstance("SHA-256");

oauth2_http/java/com/google/auth/oauth2/Slf4jUtils.java

@@ -48,6 +48,10 @@ class Slf4jUtils {
   private static boolean isSLF4J2x;
 
   static {
+    // this class was added as part of the Fluent API introduced since v2.0.0
+    // (https://www.slf4j.org/manual.html#fluent), not available in v1.7.36
+    // see
+    // https://github.com/qos-ch/slf4j/commits/v_2.0.0/slf4j-api/src/main/java/org/slf4j/event/KeyValuePair.java
     isSLF4J2x = checkIfClazzAvailable("org.slf4j.event.KeyValuePair");
   }