Why the code getting executed under `if( savedData != null )`, no matter if `savedData` is set to any value or null

Question

I am learning Android but i am not much experienced with java.
I write these code to check if there is any data in

sharedPreferences

(Which i saved before using

sharedPreferences.Editor

) or not, and if there is any saved data then do something. But the code under

if (savedData != null)

Statement is always being executed, no matter if there is any value in

savedData

or not.

But when i use

if (!savedData.isEmpty()

it is doing what i meant it to do.

But i found on StackOverflow that we should not use

isEmpty()

with String because if String is

null

then

isEmpty()

will not execute.

I just wanted to know why

if (savedData != null)

is not working but

if (!savedData.isEmpty())

.

My code: Here

Log.d("isRunning : ", "True")

under

if

statement is always executing.

private String saveString = null;

    private ListView listView;

    private static List<String> listArray = new ArrayList<String>();

    private SaveListInSharedPreferences saveListInSharedPreferences = new SaveListInSharedPreferences();



@Override

protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_main);



    SharedPreferences settings = getPreferences(MODE_PRIVATE);

    String savedData = settings.getString(saveString, null);

    if (savedData != null){

        listArray = saveListInSharedPreferences.getList(savedData);

        Log.d("isRunning : ", "True" );

    }

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Answer 1

if (myString != null && !myString.isEmpty()) {
    //
}

If this doesn't work then it isn't null. If it's not working then try setting it directly equal to null beforehand, and then figuring out why that function isn't returning null . As to why myString != null doesn't work by itself, here's a post that can explain it better than I could. Avoiding != null statements

Why the code getting executed under `if( savedData != null )`, no matter if `savedData` is set to any value or null

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