I have a POJO that I want to save, with the following methods:

@BsonIgnore
public String getSecret() {
  return secret;
}

@BsonIgnore 
public void setSecret(String secret) { 
  this.secret = secret; 
} 
 
@BsonIgnore 
public void setSecret(Integer i) { 
  this.secret = ""+i; 
}

This causes an error: 

org.bson.codecs.configuration.CodecConfigurationException: Property 'secret' in TestListing, has differing data types: TypeData{type=String} and TypeData{type=Integer}

If I change the last method name to "setSecretAsInt", I get this error:

Unable to get value for property 'secretAsInt' in TestListing

I can make it work if I then add a dummy getter like this:

public Integer getSecretAsInt() { 
 return null; 
}

But that's just ugly, and shouldn't be necessary. If a property is marked as ignored, then the serialization code should ignore it, period.

Similar bug (already fixed): https://jira.mongodb.org/browse/JAVA-2620