Program: 52303
Project: 52303
Buggy source:
/** 
 * Returns an AuthenticatedUser representing the user authenticated by the given credentials.
 * @param credentials The credentials to use for authentication.
 * @return An AuthenticatedUser representing the user authenticated by the given credentials.
 * @throws GuacamoleException If an error occurs while authenticating the user, or if access is denied.
 */
public AuthenticatedUser authenticateUser(Credentials credentials) throws GuacamoleException {
  RadiusPacket radPack;
  try {
    radPack=radiusService.authenticate(credentials.getUsername(),credentials.getPassword());
  }
 catch (  GuacamoleException e) {
    logger.error("String_Node_Str",e.getMessage());
    logger.debug("String_Node_Str",e);
    radPack=null;
  }
  if (radPack == null) {
    logger.debug("String_Node_Str");
    throw new GuacamoleInvalidCredentialsException("String_Node_Str",CredentialsInfo.USERNAME_PASSWORD);
  }
 else   if (radPack instanceof AccessReject) {
    logger.debug("String_Node_Str");
    throw new GuacamoleInvalidCredentialsException("String_Node_Str",CredentialsInfo.USERNAME_PASSWORD);
  }
 else   if (radPack instanceof AccessChallenge) {
    try {
      String replyMsg=radPack.getAttributeValue("String_Node_Str").toString();
      String radState=radPack.getAttributeValue("String_Node_Str").toString();
      logger.debug("String_Node_Str",replyMsg);
      logger.debug("String_Node_Str",radState);
      Field radiusResponseField=new RadiusChallengeResponseField(credentials.getUsername(),replyMsg,radState);
      CredentialsInfo expectedCredentials=new CredentialsInfo(Collections.singletonList(radiusResponseField));
      throw new GuacamoleInsufficientCredentialsException("String_Node_Str",expectedCredentials);
    }
 catch (    UnknownAttributeException e) {
      logger.error("String_Node_Str");
      logger.debug("String_Node_Str");
      throw new GuacamoleInvalidCredentialsException("String_Node_Str",CredentialsInfo.USERNAME_PASSWORD);
    }
  }
 else   if (radPack instanceof AccessAccept) {
    try {
      AuthenticatedUser authenticatedUser=authenticatedUserProvider.get();
      authenticatedUser.init(credentials);
      return authenticatedUser;
    }
  finally {
      radiusService.disconnect();
    }
  }
 else   throw new GuacamoleInvalidCredentialsException("String_Node_Str",CredentialsInfo.USERNAME_PASSWORD);
}

Fixed version (ground truth):
/** 
 * Returns an AuthenticatedUser representing the user authenticated by the given credentials.
 * @param credentials The credentials to use for authentication.
 * @return An AuthenticatedUser representing the user authenticated by the given credentials.
 * @throws GuacamoleException If an error occurs while authenticating the user, or if access is denied.
 */
public AuthenticatedUser authenticateUser(Credentials credentials) throws GuacamoleException {
  RadiusPacket radPack;
  try {
    radPack=radiusService.authenticate(credentials.getUsername(),credentials.getPassword());
  }
 catch (  GuacamoleException e) {
    logger.error("String_Node_Str",e.getMessage());
    logger.debug("String_Node_Str",e);
    radPack=null;
  }
  if (radPack == null) {
    logger.debug("String_Node_Str");
    throw new GuacamoleInvalidCredentialsException("String_Node_Str",CredentialsInfo.USERNAME_PASSWORD);
  }
 else   if (radPack instanceof AccessReject) {
    logger.debug("String_Node_Str");
    throw new GuacamoleInvalidCredentialsException("String_Node_Str",CredentialsInfo.USERNAME_PASSWORD);
  }
 else   if (radPack instanceof AccessChallenge) {
    try {
      String replyMsg=radPack.getAttributeValue("String_Node_Str").toString();
      String radState=radPack.getAttributeValue("String_Node_Str").toString();
      logger.debug("String_Node_Str",replyMsg);
      logger.debug("String_Node_Str",radState);
      Field radiusResponseField=new RadiusChallengeResponseField(credentials.getUsername(),replyMsg,radState);
      CredentialsInfo expectedCredentials=new CredentialsInfo(Collections.singletonList(radiusResponseField));
      throw new GuacamoleInsufficientCredentialsException("String_Node_Str",expectedCredentials);
    }
 catch (    UnknownAttributeException e) {
      logger.error("String_Node_Str");
      logger.debug("String_Node_Str");
      return null;
    }
  }
 else   if (radPack instanceof AccessAccept) {
    try {
      AuthenticatedUser authenticatedUser=authenticatedUserProvider.get();
      authenticatedUser.init(credentials);
      return authenticatedUser;
    }
  finally {
      radiusService.disconnect();
    }
  }
 else   throw new GuacamoleInvalidCredentialsException("String_Node_Str",CredentialsInfo.USERNAME_PASSWORD);
}