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Static public fields are added to the class constructor at the time of class evaluation using Object. defineProperty() . The static fields and methods can be accessed from the class itself.
In Java, non-static final variables can be assigned a value either in constructor or with the declaration. But, static final variables cannot be assigned value in constructor; they must be assigned a value with their declaration.
When a field is defined as final , it has to be initialised when the object is constructed, i.e. you're allowed to assign value to it inside a constructor. A static field belongs to the class itself, i.e. one per class. A static final field is therefore not assignable in the constructor which is one per object.
Reflection is a feature in the Java programming language. It allows an executing Java program to examine or "introspect" upon itself, and manipulate internal properties of the program. For example, it's possible for a Java class to obtain the names of all its members and display them.
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));
}...
R.class.getField("_1st").get(null);
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.
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.
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