"collection" is null

[maurxce]

I have a Database class which consists of the following code:

package me.lewd.poke.database;


import me.lewd.poke.Main;
import org.dizitart.no2.Nitrite;
import org.dizitart.no2.NitriteCollection;

public class Database {

    public Nitrite db;
    public NitriteCollection pokes;
    private String dataFolder = Main.instance.getDataFolder().getAbsolutePath();

    public void startDatabase() {
        db = Nitrite.builder()
                .filePath(dataFolder + "/data/pokes.db")
                .openOrCreate();

        pokes = db.getCollection("pokes");
    }

    public Nitrite getDatabase() { return db; }
    public NitriteCollection getCollection() { return pokes; }

    public void closeDatabase() {
        if (db.hasUnsavedChanges()) db.commit();
        if (!db.isClosed()) db.close();
    }
}

The startDatabase() method is called on start.
whenever I use the getCollection() method I get this error

java.lang.NullPointerException: Cannot invoke "org.dizitart.no2.NitriteCollection.find(org.dizitart.no2.Filter)" because "collection" is null

Using nitrite 3.4.4

[anidotnet]

Which version of JDK are you using? And please paste full stacktrace here.