Какие знаешь примеры использования паттерна Builder в Java

public class User {
    private final String firstName;
    private final String lastName;
    private final int age;
    private final String email;

    private User(UserBuilder builder) {
        this.firstName = builder.firstName;
        this.lastName = builder.lastName;
        this.age = builder.age;
        this.email = builder.email;
    }

public static class UserBuilder {
    private final String firstName;
    private final String lastName;
    private int age;
    private String email;

    public UserBuilder(String firstName, String lastName) {
        this.firstName = firstName;
        this.lastName = lastName;
    }

    public UserBuilder age(int age) {
        this.age = age;
        return this;
    }

    public UserBuilder email(String email) {
        this.email = email;
        return this;
    }

    public User build() {
        return new User(this);
    }
}

**Использование:**  
```java
User user = new User.UserBuilder("John", "Doe")
    .age(30)
    .email("john.doe@example.com")
    .build();