[1.1.0] ToOne<Some> is null

[RashidMalikov]

@Entity
public class Product {
    @Id
    private long id;
    private String title= "Product №";
    private String desc;
    public ToOne<Category> category;

    public ToOne<Category> getCategory() {
        return category;
    }

    public void setCategory(ToOne<Category> category) {
        this.category = category;
    }

    public long getId() {
        return id;
    }

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

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title= title;
    }

    public String getDesc() {
        return desc;
    }

    public void setDesc(String desc) {
        this.desc = desc;
    }
}

@Entity
public class Category {
    @Id
    private long id;
    private String title;

    public Category(String title) {
      this.title = title;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public long getId() {
        return id;
    }

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

boxStore.runInTx(new Runnable() {() ->
                    Category category = new Category("Stuff");
                    categoryBox.put(category);
                    Product product = new Product();
                    product.category.setTarget(category);  // product.category  NPE
                    productBox.put(product);
            });

product.category is null

[PavelFpv]

ToMany<> is null also for me

[manusobles]

Any workaround while it gets fixed?

[kenji47]

I took your model and tried to reproduce the error, but everything works correctly.

boxStore.runInTx(new Runnable() {
            @Override
            public void run() {
                Category category = new Category("Stuff");
                categoryBox.put(category);
                Product product = new Product();
                product.category.setTarget(category);  // all ok
                productBox.put(product);
            }
        });

[DJafari]

@RashidMalikov @PavelFpv @manusoft what is you log report for this :

Product product = new Product();
Log.v("TAG", String.format("isNull: %s", (product.category == null)));

in my environment and app it is always false

i think you must share your project to check

[manusobles]

That case is false for me too.

When using another constructor that is declared private, then it is true.
I am using private constructors with parameters (I use static method for object creation) and the moment I made it public, it is solved.

[DJafari]

@manusoft good catch, it's perhaps be a bug or limitation of magic :)
an workaround while fix this bug/limit, you can generate setter for fields of your entities, and set it manually

Product product = new Product();
product.setTitle("Stuff");
.
.
.

@greenrobot it's bug or limit ?

[manusobles]

Contructor with parameters works well as long as it is declared public. The 'problem' was that I had it declared as private.

[kenji47]

@manusoft If you debug Product creation with public and private constructors you will see the difference.

[greenrobot-team]

ObjectBox modifies the constructor by doing byte code modification to add initialization code for ToOne and ToMany fields. If you mark the constructor private, ObjectBox can not call it when creating an object, hence the ToOne and ToMany are never initialized (null). -ut

[greenrobot]

We'll investigate if we can support private constructors for a future version.

Btw, did you try package private?

[manusobles]

Setting the constructor as package private works fine.

[d-u-a-l]

I've got same problem, constructors are public and without parameters in both classes, but here's what I get:

 java.lang.RuntimeException: Unable to create application ...: java.lang.NullPointerException: Attempt to invoke virtual method 'boolean io.objectbox.relation.ToMany.addAll(java.util.Collection)' on a null object reference
    at android.app.ActivityThread.handleBindApplication(ActivityThread.java:5406)
    at android.app.ActivityThread.-wrap2(ActivityThread.java)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1545)
    at android.os.Handler.dispatchMessage(Handler.java:102)
    at android.os.Looper.loop(Looper.java:154)
    at android.app.ActivityThread.main(ActivityThread.java:6119)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'boolean io.objectbox.relation.ToMany.addAll(java.util.Collection)' on a null object reference

My classes:

@Entity
public class FavRoute {
    @Id
    public long id;
    public String name;
    public ToMany<Route> routesList;

    @Transient
    private ArrayList<Long> routeIDs;
    @Transient
    private ArrayMap<Integer, List<String>> routeNames;

    public FavRoute() {
    }
...
}

@Entity
public class Route implements Parcelable {
... static fields

    @Id(assignable = true)
    @Expose
    public long id;
    @Expose
    private byte type;
... etc

    @Transient
    private Path path;

    public Route() {
    }
...
}

Any suggestions?

[drindt]

I had the same issue. The reason in my case was that i haven't added the @Backlink annotation. I could solve that first after clearing default.json file, uninstallAll from device and feshly start over.