driver-legacy/src/main/com/mongodb/DB.java
@Deprecated
    public WriteResult removeUser(final String userName) {
        try {
            executor.execute(new com.mongodb.operation.DropUserOperation(getName(), userName, getWriteConcern()), getReadConcern());
            return new WriteResult(1, true, null);
        } catch (MongoWriteConcernException e) {
            throw createWriteConcernException(e);
        }
    }
@Deprecated
    public WriteResult removeUser(final String userName) {
        try {
            executor.execute(new com.mongodb.operation.DropUserOperation(getName(), userName, getWriteConcern()), getReadConcern());
            return new WriteResult(1, true, null);
        } catch (MongoWriteConcernException e) {
            throw createWriteConcernException(e);
        }
    }
Removes the specified user from the database.

@param userName user to be removed
@return the result of executing this operation
@throws MongoException if the operation failed
@mongodb.driver.manual administration/security-access-control/  Access Control
@deprecated Use {@code DB.command} to call the dropUser command