public abstract class ClassLoadingTest {

  public static void main(String[] args) {
    User user3 = new User();
    
  }
}

public class User {

  public static User user= new User("wang",18);
  
  public static void userSay(){
    System.out.println("调用userSay静态方法");
    user.say();
  }
  
  static{
    User.userSay();
    System.out.println("进入静态构造代码块");
    User user2333 = new User("wang2333", 19);
    user2333.say();
    user.say();
  }
  
  {
    System.out.println("进入代码块");
  }
  
  private String name;
  private int age;
  
  public User() {}
  public User(String name, int age) {
    super();
    this.name = name;
    this.age = age;
  }

  public String getName() {
    return name;
  }
  public void setName(String name) {
    this.name = name;
  }
  public int getAge() {
    return age;
  }
  public void setAge(int age) {
    this.age = age;
  }
  
  public void say(){
    System.out.println(this.getName() + "调用say方法");
  }
  
}

进入代码块
调用userSay静态方法
wang调用say方法
进入静态构造代码块
进入代码块
wang2333调用say方法
wang调用say方法
进入代码块