Connecting to mongoDB in spring boot causes errors

I want to connect to mongoDB Atlas in a spring boot project, but always Exceptions are thrown. If I use Java without spring boot, everything works fine. The following test project reproduces the errors. The pom.xml:

<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>maven-test</groupId>
<artifactId>test</artifactId>
<version>0.0.1-SNAPSHOT</version>


<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.3.1.RELEASE</version>
    <relativePath />
</parent>

<properties>
    <java.version>1.8</java.version>
</properties>

<build>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
        </plugin>
    </plugins>
</build>

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
        <exclusions>
            <exclusion>
                <groupId>org.junit.vintage</groupId>
                <artifactId>junit-vintage-engine</artifactId>
            </exclusion>
        </exclusions>
    </dependency>

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

    <dependency>
        <groupId>org.mongodb</groupId>
        <artifactId>mongodb-driver-core</artifactId>
    </dependency>

</dependencies>

</project>

The Main-class:

package test;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.data.mongo.MongoDataAutoConfiguration;
import org.springframework.boot.autoconfigure.mongo.MongoAutoConfiguration;

@SpringBootApplication(exclude = {MongoAutoConfiguration.class, MongoDataAutoConfiguration.class})
public class Main {

    public static void main(String[] args) {
        SpringApplication.run(Main.class, args);
    }

}

And the configuration for mongoDB:

package test;

import com.mongodb.ConnectionString;
import com.mongodb.MongoClientSettings;
import com.mongodb.client.MongoClient;
import com.mongodb.client.MongoClients;
import org.bson.codecs.configuration.CodecRegistry;
import org.bson.codecs.pojo.PojoCodecProvider;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import static org.bson.codecs.configuration.CodecRegistries.fromProviders;
import static org.bson.codecs.configuration.CodecRegistries.fromRegistries;

@Configuration
public class MongoConfig {

    @Value("${spring.data.mongodb.uri}")
    private String connectionString;

    @Bean
    public MongoClient mongoClient() {
        System.out.println(this.connectionString);
        CodecRegistry pojoCodecRegistry = fromProviders(PojoCodecProvider.builder().automatic(true).build());
        CodecRegistry codecRegistry = fromRegistries(MongoClientSettings.getDefaultCodecRegistry(), pojoCodecRegistry);
        return MongoClients.create(MongoClientSettings.builder()
                                                      .applyConnectionString(new ConnectionString(connectionString))
                                                      .codecRegistry(codecRegistry)
                                                      .build());
    }
}

The uri for mongoDB is stored in application.properties. If I start the server, the following exeception is thrown:

com.mongodb.MongoSocketWriteException: Exception sending message
at com.mongodb.internal.connection.InternalStreamConnection.translateWriteException(InternalStreamConnection.java:550) ~[mongodb-driver-core-4.0.4.jar:na]
at com.mongodb.internal.connection.InternalStreamConnection.sendMessage(InternalStreamConnection.java:432) ~[mongodb-driver-core-4.0.4.jar:na]
at com.mongodb.internal.connection.InternalStreamConnection.sendCommandMessage(InternalStreamConnection.java:272) ~[mongodb-driver-core-4.0.4.jar:na]
at com.mongodb.internal.connection.InternalStreamConnection.sendAndReceive(InternalStreamConnection.java:256) ~[mongodb-driver-core-4.0.4.jar:na]
at com.mongodb.internal.connection.CommandHelper.sendAndReceive(CommandHelper.java:83) ~[mongodb-driver-core-4.0.4.jar:na]
at com.mongodb.internal.connection.CommandHelper.executeCommand(CommandHelper.java:33) ~[mongodb-driver-core-4.0.4.jar:na]
at com.mongodb.internal.connection.InternalStreamConnectionInitializer.initializeConnectionDescription(InternalStreamConnectionInitializer.java:103) ~[mongodb-driver-core-4.0.4.jar:na]
at com.mongodb.internal.connection.InternalStreamConnectionInitializer.initialize(InternalStreamConnectionInitializer.java:60) ~[mongodb-driver-core-4.0.4.jar:na]
at com.mongodb.internal.connection.InternalStreamConnection.open(InternalStreamConnection.java:128) ~[mongodb-driver-core-4.0.4.jar:na]
at com.mongodb.internal.connection.DefaultServerMonitor$ServerMonitorRunnable.run(DefaultServerMonitor.java:117) ~[mongodb-driver-core-4.0.4.jar:na]
at java.lang.Thread.run(Thread.java:745) [na:1.8.0_41]

Caused by: javax.net.ssl.SSLException: java.lang.RuntimeException: Unexpected error: java.security.InvalidAlgorithmParameterException: the trustAnchors parameter must be non-empty

So I have tried to disable ssl through adding to the uri: &ssl=false However, then another exception is thrown:

com.mongodb.MongoSocketReadException: Prematurely reached end of stream
at com.mongodb.internal.connection.SocketStream.read(SocketStream.java:112) ~[mongodb-driver-core-4.0.4.jar:na]
at com.mongodb.internal.connection.InternalStreamConnection.receiveResponseBuffers(InternalStreamConnection.java:579) ~[mongodb-driver-core-4.0.4.jar:na]
at com.mongodb.internal.connection.InternalStreamConnection.receiveMessage(InternalStreamConnection.java:444) ~[mongodb-driver-core-4.0.4.jar:na]
at com.mongodb.internal.connection.InternalStreamConnection.receiveCommandMessageResponse(InternalStreamConnection.java:298) ~[mongodb-driver-core-4.0.4.jar:na]
at com.mongodb.internal.connection.InternalStreamConnection.sendAndReceive(InternalStreamConnection.java:258) ~[mongodb-driver-core-4.0.4.jar:na]
at com.mongodb.internal.connection.CommandHelper.sendAndReceive(CommandHelper.java:83) ~[mongodb-driver-core-4.0.4.jar:na]
at com.mongodb.internal.connection.CommandHelper.executeCommand(CommandHelper.java:33) ~[mongodb-driver-core-4.0.4.jar:na]
at com.mongodb.internal.connection.InternalStreamConnectionInitializer.initializeConnectionDescription(InternalStreamConnectionInitializer.java:103) ~[mongodb-driver-core-4.0.4.jar:na]
at com.mongodb.internal.connection.InternalStreamConnectionInitializer.initialize(InternalStreamConnectionInitializer.java:60) ~[mongodb-driver-core-4.0.4.jar:na]
at com.mongodb.internal.connection.InternalStreamConnection.open(InternalStreamConnection.java:128) ~[mongodb-driver-core-4.0.4.jar:na]
at com.mongodb.internal.connection.DefaultServerMonitor$ServerMonitorRunnable.run(DefaultServerMonitor.java:117) ~[mongodb-driver-core-4.0.4.jar:na]
at java.lang.Thread.run(Thread.java:745) [na:1.8.0_41]

I have found unfortunately no solution to solve them. Has someone encountered the same problem or knows a solution? Thank you

Answer

For everyone having the same problem: the cause was, that there were different versions in the maven repo. So mvn clean and mvn install solved the problem.