Java tutorial
import java.lang.reflect.Field; class MyClass { public byte i = 10; } public class Main { public static void main(String[] args) throws Exception { Class<?> clazz = Class.forName("MyClass"); MyClass x = (MyClass) clazz.newInstance(); Field f = clazz.getField("i"); System.out.println(f.getByte(x)); // Output: 10 f.setByte(x, (byte) 20); System.out.println(f.getByte(x)); // Output: 20 } }