driver-legacy/src/main/com/mongodb/Mongo.java
@Deprecated // NOT CURRENTLY INTENDED FOR REMOVAL
    public DB getDB(final String dbName) {
        DB db = dbCache.get(dbName);
        if (db != null) {
            return db;
        }

        db = new DB(this, dbName, createOperationExecutor());
        DB temp = dbCache.putIfAbsent(dbName, db);
        if (temp != null) {
            return temp;
        }
        return db;
    }
@Deprecated // NOT CURRENTLY INTENDED FOR REMOVAL
    public DB getDB(final String dbName) {
        DB db = dbCache.get(dbName);
        if (db != null) {
            return db;
        }

        db = new DB(this, dbName, createOperationExecutor());
        DB temp = dbCache.putIfAbsent(dbName, db);
        if (temp != null) {
            return temp;
        }
        return db;
    }
Gets a database object. Users should use {@link com.mongodb.MongoClient#getDatabase(String)} instead.

<p>
The {@link DB} class has been superseded by {@link com.mongodb.client.MongoDatabase}.  The deprecation of this method effectively
deprecates the {@link DB}, {@link DBCollection}, and {@link DBCursor} classes, among others; but in order to give users time to
migrate to the new API without experiencing a huge number of compiler warnings, those classes have not yet been formally
deprecated.
</p>

@param dbName the name of the database to retrieve
@return a DB representing the specified database
@throws IllegalArgumentException if the name is invalid
@see MongoNamespace#checkDatabaseNameValidity(String)
@deprecated This method is not currently scheduled for removal, but prefer {@link com.mongodb.MongoClient#getDatabase(String)} for
new code.  Note that {@link DB} and {@link com.mongodb.client.MongoDatabase} can be used together in the same application, whith the
same {@link MongoClient} instance.