Tell us about the design patterns you used in the project

In Java projects, I often use the following design patterns:

• Singleton — for creating a single instance of a class, for example, for a configuration manager or connection pool.
• Factory Method — for creating objects without tightly coupling to specific classes, which facilitates extensibility.
• Builder — for convenient and safe construction of complex objects with many parameters.
• Decorator — for dynamically adding functionality to objects without changing their code.
• Observer — for implementing event-driven models, for example, when subscribing to state changes.
• Strategy — for selecting an algorithm for behavior at runtime.

Example of using Builder to create an object:

public class User {
    private String name;
    private int age;

    private User(Builder builder) {
        this.name = builder.name;
        this.age = builder.age;
    }

    public static class Builder {
        private String name;
        private int age;

        public Builder setName(String name) {
            this.name = name;
            return this;
        }

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

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

// Usage:
User user = new User.Builder()
                .setName("Ivan")
                .setAge(30)
                .build();