First retrieve the field property of the class, then you can retrieve the value. If you know the type you can use one of the get methods with null (for static fields only, in fact with a static field the argument passed to the get method is ignored entirely). Otherwise you can use getType and write an appropriate switch as below:

Field f = R.class.getField("_1st");
Class<?> t = f.getType();
if(t == int.class){
    System.out.println(f.getInt(null));
}else if(t == double.class){
    System.out.println(f.getDouble(null));
                thanks. I tried but it didn't work. Exception is thrown at the operation f.getInt(null). I caught it but how come there's an exception?
                    – Viet
                Apr 21 '10 at 18:26
                Hi, the Exception e.getMessage() returns the field name, which is "_1st" and nothing else.
                    – Viet
                Apr 21 '10 at 18:41
                But what is the type of the exception? (i.e. NullPointerException, SecurityException, ...)
                    – M. Jessup
                Apr 21 '10 at 19:16
                How come the documentation never mentions that getInt() ignores the passed in argument? Spent hours on trying to get the instance of the class to pass there.
                    – Sevastyan Savanyuk
                Nov 8 '17 at 16:11
Exception handling is left as an exercise for the reader.
Basically you get the field like any other via reflection, but when you call the get method you pass in a null since there is no instance to act on.
This works for all static fields, regardless of their being final. If the field is not public, you need to call setAccessible(true) on it first, and of course the SecurityManager has to allow all of this.
                @Viet, can you clarify what didn't work about it? Perhaps post the code that you have that isn't working?
                    – Yishai
                Apr 21 '10 at 18:37
                Hi, the Exception e.getMessage() returns the field name, which is "_1st" and nothing else.
                    – Viet
                Apr 21 '10 at 18:41
        
I was following the same route (looking through the generated R class) and then I had this awful feeling it was probably a function in the Resources class. I was right. 
Found this:
Resources::getIdentifier
Thought it might save people some time. Although they say its discouraged in the docs, which is not too surprising. 
                So you inferred it was an Android question. Should have been indicated in the tags...
                    – Matthieu
                Apr 23 '15 at 15:03
                It's not an Android question, it's a Java reflection question that uses a particular example.  Questions are tagged based on their topic.
                    – Matthew Read
                Dec 19 '16 at 17:05
        
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