core-android/src/main/java/com/uber/sdk/android/core/auth/LoginManager.java
@NonNull
    public Session<?> getSession() {
        if (sessionConfiguration.getServerToken() != null) {
            return new ServerTokenSession(sessionConfiguration);
        } else if (accessTokenStorage.getAccessToken() != null) {
            return new AccessTokenSession(sessionConfiguration, accessTokenStorage);
        } else {
            throw new IllegalStateException("Tried to call getSession but not logged in or server token set.");
        }
    }
@NonNull
    public Session<?> getSession() {
        if (sessionConfiguration.getServerToken() != null) {
            return new ServerTokenSession(sessionConfiguration);
        } else if (accessTokenStorage.getAccessToken() != null) {
            return new AccessTokenSession(sessionConfiguration, accessTokenStorage);
        } else {
            throw new IllegalStateException("Tried to call getSession but not logged in or server token set.");
        }
    }
Gets session based on current {@link SessionConfiguration} and {@link AccessTokenStorage}.

@return Session to use with API requests.
@throws IllegalStateException when not logged in