Unsafe or unchecked operations warning

Question

In an app I am using SharedPrefernces to save/load (serialize/deserialize) some objects.

This is the deserialization code:

private void loadData() {

    String str = sharedPreferences.getString(PREF_TAG, null);

    byte[] bytes = Base64.decode(str, Base64.DEFAULT);

    try {
        ByteArrayInputStream bais = new ByteArrayInputStream(bytes);
        ObjectInputStream input = new ObjectInputStream(bais);
        arrayOfObjects = (ArrayList<MyObject>) input.readObject();
    } catch (Exception e) {
        Log.i("BUG", "error decoding serialized objects: " + e.toString());
    }

    if (arrayOfObjects == null) {
        Log.i("BUG", "serious problem!");
    }

}

But whenever I compile this project, the line:

arrayOfObjects = (ArrayList<MyObject>) input.readObject();

causes a warning that the class containing this method "uses unchecked or unsafe operations."

How can I get rid of this warning or change my code to be more safe?

Did you check this https://stackoverflow.com/questions/197986/what-causes-javac-to-issue-the-uses-unchecked-or-unsafe-operations-warning and this https://stackoverflow.com/questions/23749786/uses-unchecked-or-unsafe-operations — AskNilesh, Sep 04 '18 at 10:01

Oldskultxo · Accepted Answer · 2018-09-04T11:03:40.663

In this case that warinig is shown because you are parsing directly the result of

input.readObject();

That returns an Object of type Object, (that is so generic), into an ArrayList, and the compiler tries to say you that, it could be any other type of objects.

In my opinion its not an important warning if that instruction in your code is always returning ArrayList, so i would add to your method definition.

@SuppressWarnings("unchecked")

score 5 · Answer 2 · answered Jun 18 '19 at 21:03

5

I had the same problem and solved it by adding :

@SuppressWarnings("unchecked")
public class className extends AppCompatActivity {
...
}

I hope this will help

answered Jun 18 '19 at 21:03

Jhakiz

1,519
9
16

answering this way most appreciated, the accurate process – Noor Hossain Aug 02 '19 at 22:51

score 0 · Answer 3 · answered Oct 27 '19 at 18:57

0

I solved this problem with add :

@SuppressWarnings("unchecked")
public class CommLockInfoManager {

answered Oct 27 '19 at 18:57

Sana Ebadi

6,656
2
44
44

score 0 · Answer 4 · answered Mar 02 '22 at 16:21

0

To everyone who gave answer earlier. If you write

@SuppressWarnings("unchecked")

You tell to java: "Please not check what is under the command." This is not solution this error. If you want to the solve the problem you must don't use interface and select some name class.

answered Mar 02 '22 at 16:21

rates336

11
1
3

For this particular scenario, using this annotation is okay, because we know why the compiler is showing a warning and the reason behind it. So we can suppress that. – Abhishek Dutt Mar 06 '22 at 04:14
This does not provide an answer to the question. Once you have sufficient [reputation](https://stackoverflow.com/help/whats-reputation) you will be able to [comment on any post](https://stackoverflow.com/help/privileges/comment); instead, [provide answers that don't require clarification from the asker](https://meta.stackexchange.com/questions/214173/why-do-i-need-50-reputation-to-comment-what-can-i-do-instead). - [From Review](/review/late-answers/31197292) – Abhishek Dutt Mar 06 '22 at 04:14

Unsafe or unchecked operations warning

4 Answers4