reflect permission and security manager in java

import java.lang.reflect.Field;
import java.lang.reflect.ReflectPermission;
public class  {
    private String test = "test string in class ReflectField!";
    public static void main(String[] args) throws Exception {
        Class ref = ReflectField.class;
        SecurityManager nsm = new SecurityManager();
        System.setSecurityManager(nsm);
        ReflectPermission rp = new ReflectPermission("suppressAccessChecks", null);
        System.out.println(rp);
        
        // access denied (java.lang.reflect.ReflectPermission suppressAccessChecks
        // nsm.checkPermission(rp);
        SecurityManager sm = System.getSecurityManager();
        System.out.println(sm);
        Field[] fields = ref.getDeclaredFields();
        System.out.println(fields.length);
        for (Field field : fields) {
            
            // access denied (java.lang.reflect.ReflectPermission suppressAccessChecks
            // field.setAccessible(true);
            // java.lang.IllegalArgumentException
            // at sun.reflect.UnsafeFieldAccessorImpl.ensureObj(UnsafeFieldAccessorImpl.java)
            // System.out.println(field.get(ref));
            System.out.println(field.getName());
        }
    }
}