public WebSecurityManager getWebSecurityManager() {
        SecurityManager sm = super.getSecurityManager();
        assertWebSecurityManager(sm);
        return (WebSecurityManager) sm;
    }
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