private static PropertySource<?> loadEnvironmentAndSystemProperties() {
        val source = new CompositePropertySource("environmentAndSystemProperties");
        source.addPropertySource(new PropertiesPropertySource(StandardEnvironment.SYSTEM_PROPERTIES_PROPERTY_SOURCE_NAME, System.getProperties()));
        source.addPropertySource(new SystemEnvironmentPropertySource(StandardEnvironment.SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME, (Map) System.getenv()));
        return source;
    }
Returns a property source composed of system properties and environment variables.
<p>
System properties take precedence over environment variables (similarly to spring boot behaviour).
core/cas-server-core-configuration-api/src/main/java/org/apereo/cas/configuration/DefaultCasConfigurationPropertiesSourceLocator.java