java.lang.noSuchMethodError with .iterator or .into when using .find

Working with Data Drivers
1

I’m attempting to build my own application and backend API to further my understanding of the Mongo Java driver after completing the M220J course, but am running into a blocker.

Context

I’m creating a bookmark managing app and rebuilding the backend in Java using the Mongo driver and Spring Boot. The error appears when using .iterator() or .into() after .find() to query my Atlas database. The error DOES NOT APPEAR when using .first() after .find().

My pom.xml includes version 4.2.2 of mongodb-driver-sync. I’m using Java 15.0.1.

The folders collection uses a CodecRegistry, much like how the Users or Sessions collection is created in the mflix app, meaning a query on foldersCollection should return documents of type Folder. I’ve verified that the data has the same fields in the database and Folder.java class.

Code

In the code, the user_id field is currently stored as a String, not ObjectId, in the Folder documents (acts like a foreign key) This does not cause the error. The .into() trick was taken from this article talking about Mongo and Java Pojos.

  // Returns an array of folders, given a user id
  public List<Folder> getFolders(String id) {
    if (id == null || id.isEmpty()) return null;
    List<Folder> folders = foldersCollection.find(new Document("user_id", id)).into(new ArrayList<>());
    return folders;
  }

This code also does not work, which uses .iterator() after .find(), and excludes the id to get all folders. It also does not work if I include the id in the query.

  public List<Folder> getAllFolders(){
    List<Folder> folders = new ArrayList<>();
    foldersCollection.find().iterator().forEachRemaining(folders::add);
    return folders;
  }

I have verified that this code works with a test in Java and in Postman:

  // Gets a folder from db given folder _id
  public Folder getFolder(String id) {
    if (id == null || id.isEmpty()) return null;
    return foldersCollection.find(new Document("_id", new ObjectId(id))).first();
  }

NoSuchMethodError:

It looks like it’s pointing towards the .find() method when I use .into(), but I’ve confirmed that .find() works when chained with .first(), so I don’t think .find() is the issue. The same error appears when using .iterator().


java.lang.NoSuchMethodError: 'com.mongodb.internal.operation.ExplainableReadOperation com.mongodb.internal.operation.SyncOperations.find(org.bson.conversions.Bson, java.lang.Class, com.mongodb.internal.client.model.FindOptions)'

	at com.mongodb.client.internal.FindIterableImpl.asReadOperation(FindIterableImpl.java:236)
	at com.mongodb.client.internal.FindIterableImpl.asReadOperation(FindIterableImpl.java:40)
	at com.mongodb.client.internal.MongoIterableImpl.execute(MongoIterableImpl.java:135)
	at com.mongodb.client.internal.MongoIterableImpl.iterator(MongoIterableImpl.java:92)
	at com.mongodb.client.internal.MongoIterableImpl.forEach(MongoIterableImpl.java:121)
	at com.mongodb.client.internal.MongoIterableImpl.into(MongoIterableImpl.java:130)
	at com.bookmarkd.api.daos.FolderDao.getFolders(FolderDao.java:46)
    at com.bookmarkd.FolderTest.GetFolders(FolderTest.java:50) <31 internal lines>
    at java.base/java.util.ArrayList.forEach(ArrayList.java:1511) <9 internal lines>
    at java.base/java.util.ArrayList.forEach(ArrayList.java:1511) <23 internal lines>

Lastly, here’s my Folder class and an image a of a few documents in the Atlas database:

public class Folder {

  @BsonId
  @JsonIgnore
  private ObjectId oid;

  @JsonProperty("_id")
  @BsonIgnore
  private String id;

  @JsonProperty("user_id")
  private String userId;

  private String name;
  private String icon;
  private boolean shareable;

  // Constructor, getters, and setters... 
}

image
image788×956 83.5 KB

I know this is a lot of info, but any help or advice to solve this issue is greatly appreciated!

2

Hi Ian,
I tested your code locally and it works just fine.
It looks like maven or you IDE is using an old version of driver-core.
if you are setting it manually in your pom, remove it. the mongodb-driver-sync will take care of it.
otherwise, clean your caches. if it still doesn’t work, share your pom file
Regards

1 Like
3

Sorry for the late reply Imad_Bouteraa, but the solution was actually a version issue between three Maven dependencies. I thought that you only needed mongodb-driver-sync in the pom.xml, but for me, I also had to include the same version of mongodb-driver-core and the bson artifact from org.mongodb.

If I didn’t specify all three dependencies in the pom.xml file, the error occurs because mongodb-driver-sync runs at version 4.2.2, but the other dependencies run at version 4.2.1. I looked in the External Libraries folder to see the versions.

I was able to update all three to version 4.2.3 by specifying them in the pom.xml, and the app works!

I wish the documentation could have been clearer about requiring all three in the pom.xml, but there could have been an issue on my end in Maven or IntelliJ when resolving the dependencies. I tried so many times to comment out the dependency, reload the project, clear cache, and redownload, only to have the same error come back!

<!-- THIS MAKES THE APP WORK! -->

<!-- https://mvnrepository.com/artifact/org.mongodb/mongodb-driver-sync -->
<dependency>
	<groupId>org.mongodb</groupId>
	<artifactId>mongodb-driver-sync</artifactId>
	<version>4.2.3</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.mongodb/mongodb-driver-core -->
<dependency>
	<groupId>org.mongodb</groupId>
	<artifactId>mongodb-driver-core</artifactId>
	<version>4.2.3</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.mongodb/bson -->
<dependency>
	<groupId>org.mongodb</groupId>
	<artifactId>bson</artifactId>
	<version>4.2.3</version>
</dependency>
4 Likes
4

Glad for you :partying_face:

mongodb-driver-sync define its required dependencies with the exact versions. it should be Maven or IntelliJ

https://mvnrepository.com/artifact/org.mongodb/mongodb-driver-sync/4.2.3

check this link, it may help in future troubleshooting

Regards,

1 Like