Here is an example of how to use the MutableConfigOverride class in the com.fasterxml.jackson.databind package in Java:

import com.fasterxml.jackson.databind.MutableConfigOverride;

public class MyClass {

    public static void main(String[] args) {
        MutableConfigOverride config = new MutableConfigOverride();
        config.setFormat(MutableConfigOverride.Feature.WRITE_DATE_TIMESTAMPS_AS_NANOSECONDS, false);
        // use config to configure an ObjectMapper instance
    }
}

In this example, a new instance of MutableConfigOverride is created, and its setFormat method is used to configure the WRITE_DATE_TIMESTAMPS_AS_NANOSECONDS feature to be false. This config object can then be used to configure an ObjectMapper instance.

Keep in mind that this is just an example, you can configure different features based on your requirement.