Java – Android: Cannot call private without parameters

Android: Cannot call private without parameters… here is a solution to the problem.

Android: Cannot call private without parameters

I’m using Gson to save an array list of custom models to a shared preference

Storage Code:

ArrayList<DownloadProgressDataModel> arrayList = getArrayListFromPref(downloadProgressDataModel);
        SharedPreferences.Editor prefsEditor = getSharedPreferences("APPLICATION_PREF", MODE_PRIVATE).edit();

Gson gson = new Gson();
        String json = gson.toJson(arrayList);
        prefsEditor.putString("DownloadManagerList", json);


ArrayList<DownloadProgressDataModel> arrayList;
        Gson gson = new Gson();

SharedPreferences  mPrefs = getSharedPreferences("APPLICATION_PREF", MODE_PRIVATE);
        String json = mPrefs.getString("DownloadManagerList", "");

if (json.isEmpty()) {
            arrayList = new ArrayList<DownloadProgressDataModel>();
        } else {
            Type uriPath = new TypeToken<ArrayList<DownloadProgressDataModel>>() {
            arrayList = gson.fromJson(json, uriPath);  <------ Error line

But on the error line I get: Unable to instantiate class

Model number

public class DownloadProgressDataModel {
    private Uri uriPath;
    private long referenceId;

public Uri getUriPath() {
        return uriPath;

public void setUriPath(Uri uriPath) {
        this.uriPath = uriPath;

public long getReferenceId() {
        return referenceId;

public void setReferenceId(long referenceId) {
        this.referenceId = referenceId;


The Uri class constructor is private, it is an abstract class. Gson tries to create a new object for the Uri class using the reflection API (we can’t create an object for an abstract class). Such a simple solution is to change the uriPath to a String instead of a URI.

 private String uriPath;

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