How to get client app id at runtime on oauth2 server - spring boot

Question

I am new to Spring boot and implementing oauth server where I want to use oauth2 authorization grant type flow. I have multiple clinet apps and each client app has its own ldap group to authenticate the user. I wonder how I can get client app id at runtime during user authentication?

@Override
public Authentication authenticate(Authentication authentication) throws AuthenticationException {
    String username = authentication.getName();
    String password = authentication.getCredentials().toString();
    if(userName != null && password != null) {
        String clientId = //CLIENT_ID
        //Get client Ldap group using clientId from db and autheticate the user
    } else {
        throw new BadCredentialsException("Invalid Client Credentials");
    }     
}