<dependency>
    <groupId>org.mongodb</groupId>
    <artifactId>mongodb-driver-sync</artifactId>
    <version>4.11.1</version>
</dependency>

implementation 'org.mongodb:mongodb-driver-sync:4.11.1'

package com.example.mongodb;

import com.mongodb.ConnectionString;
import com.mongodb.MongoClientSettings;
import com.mongodb.client.*;
import com.mongodb.client.model.Filters;
import org.bson.Document;

import java.util.concurrent.TimeUnit;

public class MongoDBDemo {

    public static void main(String[] args) {
        // Connection URI (Replace with your actual connection information)
        // Replica set connection string format:
        // mongodb://mongouser:<password>@<IP1>:27017,<IP2>:27017,<IP3>:27017/admin?replicaSet=cmgo-xxxxxxxx_0
        String uri = "mongodb://mongouser:thepasswordA1@10.66.187.127:27017/admin";

        // Configure connection parameters (including connection pool settings)
        MongoClientSettings settings = MongoClientSettings.builder()
                .applyConnectionString(new ConnectionString(uri))
                .applyToConnectionPoolSettings(builder -> builder
                        .maxSize(50)              // Maximum size of the connection pool
                        .minSize(5)               // Minimum size of the connection pool
                        .maxWaitTime(5, TimeUnit.SECONDS)  // Timeout for waiting for an available connection
                        .maxConnectionIdleTime(60, TimeUnit.SECONDS))  // Idle connection timeout
                .applyToSocketSettings(builder -> builder
                        .connectTimeout(10, TimeUnit.SECONDS)  // Connection timeout
                        .readTimeout(30, TimeUnit.SECONDS))    // Read timeout
                .retryWrites(true)    // Enable retryable writes
                .retryReads(true)     // Enable retryable reads
                .build();

        // Create a client connection (automatically closed using try-with-resources)
        try (MongoClient mongoClient = MongoClients.create(settings)) {
            // Select a database.
            MongoDatabase database = mongoClient.getDatabase("mydb");

            // Obtain a collection.
            MongoCollection<Document> collection = database.getCollection("users");

            // Insert a document.
            Document doc = new Document("username", "jack")
                    .append("age", 31)
                    .append("email", "jack@example.com");
            collection.insertOne(doc);
            System.out.println("Inserted document: " + doc.toJson());

            // Query the document
            Document result = collection.find(Filters.eq("username", "jack")).first();
            if (result != null) {
                System.out.println("Query result: " + result.toJson());
            }

            // Update the document.
            collection.updateOne(
                    Filters.eq("username", "jack"),
                    new Document("$set", new Document("age", 32))
            );
            System.out.println("Update completed.");

            // Delete the document.
            collection.deleteOne(Filters.eq("username", "jack"));
            System.out.println("Deletion completed.");

        } catch (Exception e) {
            System.err.println("Database operation failed: " + e.getMessage());
            e.printStackTrace();
        }
    }
}

Insert a document: {"username": "jack", "age": 31, "email": "jack@example.com", "_id": {"$oid": "6789abcdef1234567890abcd"}}
Query result: {"_id": {"$oid": "6789abcdef1234567890abcd"}, "username": "jack", "age": 31, "email": "jack@example.com"}
The update is completed.
Deletion completed.

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-mongodb</artifactId>
</dependency>

spring:
  data:
    mongodb:
      uri: mongodb://mongouser:thepasswordA1@10.66.187.127:27017/mydb?authSource=admin
      # Replica set connection string:
      # uri: mongodb://mongouser:thepasswordA1@IP1:27017,IP2:27017,IP3:27017/mydb?authSource=admin&replicaSet=cmgo-xxxxxxxx_0

import org.springframework.data.annotation.Id;
import org.springframework.data.mongodb.core.mapping.Document;

@Document(collection = "users")
public class User {
    @Id
    private String id;
    private String username;
    private Integer age;
    private String email;

    // Constructors, getters, and setters are omitted.
}

import org.springframework.data.mongodb.repository.MongoRepository;

public interface UserRepository extends MongoRepository<User, String> {
    User findByUsername(String username);
}

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.stereotype.Component;

@Component
public class MongoDBRunner implements CommandLineRunner {

    @Autowired
    private UserRepository userRepository;

    @Override
    public void run(String... args) {
        // Insert a document
        User user = new User();
        user.setUsername("jack");
        user.setAge(31);
        user.setEmail("jack@example.com");
        userRepository.save(user);

        // Query the document
        User found = userRepository.findByUsername("jack");
        System.out.println("Query result: " + found);
    }
}

com.mongodb.MongoSecurityException: Exception authenticating MongoCredential{mechanism=SCRAM-SHA-1, userName='mongouser', source='admin', ...}
Caused by: com.mongodb.MongoCommandException: Command failed with error 18 (AuthenticationFailed)

com.mongodb.MongoTimeoutException: Timed out after 30000 ms while waiting to connect. Client view of cluster state is {type=UNKNOWN, servers=[...]

com.mongodb.MongoSocketReadException: Prematurely reached end of stream

MongoClientSettings settings = MongoClientSettings.builder()
        .applyConnectionString(new ConnectionString(uri))
        .applyToConnectionPoolSettings(builder -> builder
                .maxConnectionIdleTime(60, TimeUnit.SECONDS))  // Automatically closes idle connections after 60 seconds
        .build();