java plugin

MyPlugin.java

import java.util.List;
import javax.persistence.PersistenceException;
import org.bukkit.plugin.java.JavaPlugin;

public class MyPlugin extends JavaPlugin {

    @Override
    public void onLoad() {
        //some more code
        setupDatabase();
    }

    @Override
    public List<Class<?>> getDatabaseClasses() {
        List<Class<?>> classes = super.getDatabaseClasses();
        classes.add(ToBeSaved.class);
        return classes;
    }

    private void setupDatabase() {
        try {
            getDatabase().find(ToBeSaved.class).findRowCount();
        } catch (PersistenceException e) {
            installDDL();
        }
    }
}

ToBeSaved.java

import com.avaje.ebean.validation.NotNull;
import java.io.Serializable;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

@Entity
public class ToBeSaved implements Serializable {
    private static final long serialVersionUID = 3611041942327901641L;
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;
    @NotNull
    private String name;

    public Relation() {}

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

}