code: package mirror;
  
  import java.lang.reflect.Constructor;
  import java.lang.reflect.Field;
  
  public class RefConstructor<T> {
      private Constructor<?> ctor;
  
      public RefConstructor(Class<?> cls, Field field) throws NoSuchMethodException {
          if (field.isAnnotationPresent(MethodParams.class)) {
              Class<?>[] types = field.getAnnotation(MethodParams.class).value();
              ctor = cls.getDeclaredConstructor(types);
          } else if (field.isAnnotationPresent(MethodReflectParams.class)) {
              String[] values = field.getAnnotation(MethodReflectParams.class).value();
              Class[] parameterTypes = new Class[values.length];
              int N = 0;
              while (N < values.length) {
                  try {
                      parameterTypes[N] = Class.forName(values[N]);
                      N++;
                  } catch (Exception e) {
                      e.printStackTrace();
                  }
              }
              ctor = cls.getDeclaredConstructor(parameterTypes);
          } else {
              ctor = cls.getDeclaredConstructor();
          }
          if (ctor != null && !ctor.isAccessible()) {
              ctor.setAccessible(true);
          }
      }
  
      public T newInstance() {
          try {
              return (T) ctor.newInstance();
          } catch (Exception e) {
              return null;
          }
      }
  
      public T newInstance(Object... params) {
          try {
              return (T) ctor.newInstance(params);
          } catch (Exception e) {
              return null;
          }
      }
  }