public class TestField{
public int var1 = 0;
public int var2 = 0;
public int var3 = 0;
public static void main(String[] args){
try{
Class c = Class.forName("TestField");
TestField obj = (TestFiled)c.newInstance();
for(int i = 1; i <= 3; i++){
Field field = c.getField("var" + i);
field.setInt(obj, i);