Get constructor and its parameters and call constructor with parameter

 
import java.lang.reflect.Constructor;

public class Main {
  public static void main(String args[]) throws Exception {
    Class c = Class.forName("MyClass");

    Constructor constructors[] = c.getDeclaredConstructors();
    Object obj = null;
    for (Constructor cons : constructors) {
      Class[] params = cons.getParameterTypes();
      if (params.length == 1 && params[0] == int.class) {
        obj = cons.newInstance(10);
        break;
      }
    }
  }
}

class MyClass {
  private int count;

  MyClass(int c) {
    System.out.println("MyClass(int):" + c);
    count = c;
  }

  MyClass() {
    System.out.println("MyClass()");
    count = 0;
  }

  void setCount(int c) {
    System.out.println("setCount(int): " + c);
    count = c;
  }

  int getCount() {
    System.out.println("getCount():" + count);
    return count;
  }

  void showcount() {
    System.out.println("count is " + count);
  }
}