@Override
    public ShiroFilterConfiguration getShiroFilterConfiguration() {
        ShiroFilterConfiguration config = getObject(SHIRO_FILTER_CONFIG_NAME, ShiroFilterConfiguration.class);
        // Use the default configuration if config is null
        if (config == null) {
            config = MutableWebEnvironment.super.getShiroFilterConfiguration();
            setShiroFilterConfiguration(config);
        }
        return config;
    }
Default {@link WebEnvironment} implementation based on a backing {@link Map} instance.

@since 1.2
web/src/main/java/org/apache/shiro/web/env/DefaultWebEnvironment.java