Help for creating own library (add java file to sketch)

Processing Libraries
4

Thanks for you answer but it did not work for me.
File name is called Addressbook store in sketch folder.
Class Name Addressbook
When I save Addressbook.pde as Addressbook.java An error like this:
The sketch name had to be modified. Sketch names can only consist of ASCII characters and numbers (but cannot start with a number). They should also be less than 64 characters long.
And the new filename named Addressbook_java gets created.
here is mine class:

class Addressbook{
  private int id;
  private String name;

  public Addressbook(
    int id,
    String name) {
    this.name = name;
    this.id = id;
  }

  public String toString() {
    return id + " { " + name;
  }
  
  public String getName() {
    return name;
  }
  
  public int getID() {
    return id;
  }
}

class Adressbook {
  private String name;
  private Addressbook[] contacts;

  public Adressbook(String name) {
    this.name = name;
    this.contacts = new Addressbook[0];
  }

  public String showAll() {
    String output = "Adressbuch { " +name +"\n";
    for (int i = 0; i < contacts.length; i++) {
      output = output + contacts[i].toString() + "\n";
    }
    return output;
  }

  public String showByName(String name) {
    for (int i = 0; i < contacts.length; i++) {
      if (contacts[i].getName() == name) {
        return contacts[i].toString();
      }
    }
    return "";
  }

  public void addContact(Addressbook contact) {
    Addressbook[] contactsNew = new Addressbook[contacts.length + 1];
    for (int i = 0; i < contacts.length; i++) {
      contactsNew[i] = contacts[i];
    }
    contactsNew[contactsNew.length -1] = contact;
    contacts = contactsNew;
  }
  
  public Addressbook getContact(int id) {
    for (int i = 0; i < contacts.length; i++) {
      if (contacts[i].getID() == id) {
        return contacts[i];
      }
    }
    return null;
  }

  public void removeContact(int id) {
    Addressbook[] contactsCopy = new Addressbook[0];
    for (int i = 0; i < contacts.length; i++) {
      if (contacts[i].getID() != id) {
        Addressbook[] contactsCopyNew = new Addressbook[contactsCopy.length +1];
        for (int j = 0; j < contactsCopy.length; j ++) {
          contactsCopyNew[j] = contactsCopy[j];
        }
        contactsCopyNew[contactsCopyNew.length -1] = contacts[i];
        contactsCopy = contactsCopyNew;
      }
    }
    this.contacts = contactsCopy;
  }
}

and the new sketch 
import Addressbook;

public void setup() {
  Adressbook privat = new Adressbook("Privat");
  privat.addContact(new Contact(1, "ken Tern"));
  privat.addContact(new Contact(2, "jlkjlldk"));
  privat.addContact(new Contact(3, "lkjljlkj"));
  print(privat.showAll());
}

I know you me using without import but this did also not work.