Chinese mapping number routing
You could simply put your maps in a map, as the mapRouting function is nothing but a simple lookup.

Prepare somewhere

private static final Map&lt;String, Map&lt;String, String&gt;&gt; MASTER = new HashMap&lt;&gt;() {
   {
       put("ACTION", ACTION);
       put("ENVIRONMENT", ENVIRONMENT);
       put("RULE_TYPE", RULE_TYPE);
   }
};


And simply access that map:

public static Map&lt;String, String&gt; mapRouting(String mapName) {
    return MASTER.get(mapName);
}


BTW: in times of Java 10 you should really use Map.of instead of anonymous map subclasses.