Java - java.io.NotSerializableException: net.sourceforge.jtds.jdbc.JtdsConnection

Question

I'd like to share a class from activity to another. I tried everything, searched everywhere, but can't solve my problem. The most important is that I have to use BusinessLogic as a controll class of the whole App. Every variable, methods are in it.. Could somebody help me out?

public void ConnectSQL() {
    StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
    StrictMode.setThreadPolicy(policy);
    try {
        Class.forName("net.sourceforge.jtds.jdbc.Driver");
        con = DriverManager.getConnection("jdbc:jtds:sqlserver://192.168.3.10;databaseName=hungary;user=stockiduser;password=Berwin1559;loginTimeout=5;socketTimeout=5");
        KapcsolatAllasKijelzes(false);
    } catch (Exception e) {
        KapcsolatAllasKijelzes(true);
    }
}

This method located is in my class named BusinessLogic... Here is MainActivity code:

Intent intent=new Intent(this, Kiszedes.class);
intent.putExtra("bl",bl);
startActivity(intent);

Kiszedes.class is the target activity:

 BusinessLogic bl = (BusinessLogic) getIntent().getSerializableExtra("bl");

Here is what LogCat says:

proba.diszpo E/AndroidRuntime: FATAL EXCEPTION: main
Process: proba.diszpo, PID: 11721
java.lang.RuntimeException: Parcelable encountered IOException writing serializable object (name = proba.diszpo.BusinessLogic)
    at android.os.Parcel.writeSerializable(Parcel.java:1526)
    at android.os.Parcel.writeValue(Parcel.java:1474)
    at android.os.Parcel.writeArrayMapInternal(Parcel.java:723)
    at android.os.BaseBundle.writeToParcelInner(BaseBundle.java:1408)
    at android.os.Bundle.writeToParcel(Bundle.java:1133)
    at android.os.Parcel.writeBundle(Parcel.java:763)
    at android.content.Intent.writeToParcel(Intent.java:8660)
    at android.app.ActivityManagerProxy.startActivity(ActivityManagerNative.java:3154)
    at android.app.Instrumentation.execStartActivity(Instrumentation.java:1518)
    at android.app.Activity.startActivityForResult(Activity.java:4226)
    at android.support.v4.app.BaseFragmentActivityJB.startActivityForResult(BaseFragmentActivityJB.java:48)
    at android.support.v4.app.FragmentActivity.startActivityForResult(FragmentActivity.java:77)
    at android.app.Activity.startActivityForResult(Activity.java:4185)
    at android.support.v4.app.FragmentActivity.startActivityForResult(FragmentActivity.java:859)
    at android.app.Activity.startActivity(Activity.java:4509)
    at android.app.Activity.startActivity(Activity.java:4477)
    at proba.diszpo.MainActivity.onClick(MainActivity.java:177)
    at android.view.View.performClick(View.java:5675)
    at android.view.View$PerformClick.run(View.java:22641)
    at android.os.Handler.handleCallback(Handler.java:836)
    at android.os.Handler.dispatchMessage(Handler.java:103)
    at android.os.Looper.loop(Looper.java:203)
    at android.app.ActivityThread.main(ActivityThread.java:6251)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1063)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:924)
Caused by: java.io.NotSerializableException: net.sourceforge.jtds.jdbc.JtdsConnection
    at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1224)
    at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1584)
    at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1549)
    at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1472)
    at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1218)
    at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:346)
    at android.os.Parcel.writeSerializable(Parcel.java:1521)
    at android.os.Parcel.writeValue(Parcel.java:1474) 
    at android.os.Parcel.writeArrayMapInternal(Parcel.java:723) 
    at android.os.BaseBundle.writeToParcelInner(BaseBundle.java:1408) 
    at android.os.Bundle.writeToParcel(Bundle.java:1133) 
    at android.os.Parcel.writeBundle(Parcel.java:763) 
    at android.content.Intent.writeToParcel(Intent.java:8660) 
    at android.app.ActivityManagerProxy.startActivity(ActivityManagerNative.java:3154) 
    at android.app.Instrumentation.execStartActivity(Instrumentation.java:1518) 
    at android.app.Activity.startActivityForResult(Activity.java:4226) 
    at android.support.v4.app.BaseFragmentActivityJB.startActivityForResult(BaseFragmentActivityJB.java:48) 
    at android.support.v4.app.FragmentActivity.startActivityForResult(FragmentActivity.java:77) 
    at android.app.Activity.startActivityForResult(Activity.java:4185) 
    at android.support.v4.app.FragmentActivity.startActivityForResult(FragmentActivity.java:859) 
    at android.app.Activity.startActivity(Activity.java:4509) 
    at android.app.Activity.startActivity(Activity.java:4477) 
    at proba.diszpo.MainActivity.onClick(MainActivity.java:177) 
    at android.view.View.performClick(View.java:5675) 
    at android.view.View$PerformClick.run(View.java:22641) 
    at android.os.Handler.handleCallback(Handler.java:836) 
    at android.os.Handler.dispatchMessage(Handler.java:103) 
    at android.os.Looper.loop(Looper.java:203) 
    at android.app.ActivityThread.main(ActivityThread.java:6251) 
    at java.lang.reflect.Method.invoke(Native Method) 
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1063) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:924)

Answer 1

Your BusinessLogic class contains a reference to a JtdsConnection object, which is not serializable. It's not enough for BusinessLogic to be Serializable , all of its members (and members of members, etc). need to be Serializable as well.

Since JtdsConnection is not a class you've created, you cannot make it Serializable . Anyhow, the way you're trying to make this work is not really correct.

---

I suggest having a global instance of your business logic so you'll be able to access it from any activity / fragment.

In my projects I usually create a Conf class with static instances of objects I need. In your case you could have something like this:

public class Conf {

    @Nullable
    private static BusinessLogic businessLogic;

    @NonNull
    public static BusinessLogic getBusinessLogic() {

        if (businessLogic == null) {
            businessLogic = new BusinessLogic();
        }

        return businessLogic;
    }
}

In your activity you can now simply do: BusinessLogic bl = Conf.getBusinessLogic() .