IOException returning null for get message

Question

try {
    fis = context.openFileInput("Stores");
    ObjectInputStream oi = new ObjectInputStream(fis);
    toReturn = (ArrayList<Store>) oi.readObject();
    oi.close();
} catch (FileNotFoundException e) {
    Log.e("InternalStorage", e.getMessage());
} catch (IOException e) {
    Log.e("InternalStorage", e.getMessage());
} catch (ClassNotFoundException e) {
    e.printStackTrace();
}

I have a crashlog on the IOException scope, saying

java.lang.NullPointerException: println needs a message

Why would this happen?

Or instead you can use `Log.e(String tag, String msg, Throwable tr)` — OneCricketeer, Dec 05 '16 at 17:28
The issue you have is that `e.getMessage` returns `null` and you cannot print that. You can also use `Log.getStackTraceStrin(e)` if you want the full stack trace. — fbwnd, Dec 05 '16 at 17:28
THank you. Cricket, this suggests otherwise: http://stackoverflow.com/questions/3131865/why-does-string-valueofnull-throw-a-nullpointerexception — quantumpotato, Dec 05 '16 at 17:32
You read that post wrong `String.valueOf(char[])` is throwing that exception. In your case, `String.valueOf((String) null)` works fine — OneCricketeer, Dec 05 '16 at 17:36

AmirHossein SayyadAbdi · Accepted Answer · 2016-12-05T17:49:32.830

Because IOException always returns null when you call e.getMessage(). Try to log something else when this exception occurs.

For example:

    StackTraceElement[] stackTraceElements = e2.getStackTrace();
    String logMessage = "IOException occured in method "
            + stackTraceElements[0].getMethodName() + " - File name is "
            + stackTraceElements[0].getFileName()
            + " - At line number: "
            + stackTraceElements[0].getLineNumber();
    Log.e("InternalStorage", e.getMessage());

IOException returning null for get message

1 Answers1