CODEWITHSUNDEEP
javamongodbclasscastexceptionobjectid
L. Männer
L. Männer

Reputation: 469

ClassCastException thrown even though there is no cast

I've got a HashMap<ObjectId, Integer> in which I want to add a new entry. ObjectId is a BSON class which comes with the MongoDB-Driver in my case.

 1   @Expose private Map<ObjectId, Integer> usedPaths;
 2   
 3   public Project()
 4   {
 5      this.usedPaths = new HashMap<>();
 6   }
 7
 8   public void usePath(ObjectId someId, int pathId)
 9   {
10      this.usedPaths.put(someId, pathId);
11   }
12
13   public void debug()
14   {
15      usePath(new ObjectId("5bfd98a2c06178796e66c204"), 1);
16   }

When I call the debug method, a ClassCastException is thrown:

    SCHWERWIEGEND: Servlet.service() for servlet [Jersey Web Application] in context with path [/KnowledgerServer] threw exception [java.lang.ClassCastException:
org.bson.types.ObjectId cannot be cast to java.lang.String] with root cause
java.lang.ClassCastException: org.bson.types.ObjectId cannot be cast to java.lang.String
    at org.bson.BasicBSONObject.put(BasicBSONObject.java:36)
    at de.knowledger.model.Project.usePath(Project.java:10)
    at de.knowledger.model.Project.debug(Project.java:15)

As far as I know and see I don't even try to cast an ObjectId to String, furthermore I'm never accessing the BasicBSONObject class in my code, ObjectId doesn't extend it either.

Thanks in advance :)

Upvotes: 1

Views: 702

Answers (2)

L. M&#228;nner
L. M&#228;nner

Reputation: 469

The problem was that I tried to save and load a HashMap to/from MongoDB, its Java driver handles any passed Map as DBObject.

Thank you for your Tips!

Upvotes: 0

Andy Sug
Andy Sug

Reputation: 244

There is no error in the piece of code you have provided, as far as I can see. The exception makes it clear that the class is part of a servlet. The issue could be in what is happening before and after you call the usePath(...) method.

Upvotes: 1

Related Questions