@Override
    public String toString() {
        return getClass().getSimpleName() + "(" + credentialsFilePath + ")";
    }
Creates a new PropertiesFileCredentialsProvider that will attempt to load
a custom file from the path specified to read AWS security credentials.

@param credentialsFilePath
           The custom classpath resource path to a properties file from
           which the AWS security credentials should be loaded.

           For example,
           <ul>
           <li>/etc/somewhere/credentials.properties</li>
           </ul>
aws-java-sdk-core/src/main/java/com/amazonaws/auth/PropertiesFileCredentialsProvider.java