Setting unique key constraint for Db4oEmbedded EmbeddedConfiguration

I want to set unique key constraint for Db4oEmbedded EmbeddedConfiguration.

Here goes my code:

EmbeddedConfiguration myConf = Db4oEmbedded.newConfiguration();

myConf.common().objectClass(NotyUser.class).objectField("username").indexed(true);

myConf.common().add(new com.db4o.constraints.UniqueFieldValueConstraint(NotyUser.class, "username"));

The last line throws exception. I don't know why. I'm running Android SDK 1.5 and db4o 7.12 for Java. Please kindly开发者_如何学运维 advise. Thanks!

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I ran the code snippet you posted with a simple NotyUser class (just a String username field) and no exception was thrown neither in db4o-7.12 in android 1.5, nor db4o trunk with android 2.1.

What exception was thrown there? and can you post the NotyUser class?