You can use the AEM API to get information about AEM resources such as pages. In your code, you can use the following code.
PageManager pageManager = resourceResolver.adaptTo(PageManager.class);
Page listPage = pageManager.getPage("/etc/acs-commons/lists/targets");
GenericList list = listPage.adaptTo(GenericList.class);
String value = list.lookup(key);
This code gives you the value. For more information about using Sling APIs, see Using Sling APIs to retrieve content from the Adobe Experience Manager Repository.