Java buffered writer wont write all data

Question

public static void save() 
{
    BufferedWriter out = null;
    try 
    {
        out = new BufferedWriter(new OutputStreamWriter(Gdx.files.external(file).write(false)));
        out.write(Double.toString(FinanceSystem.currentPlayerCash));
        out.write("\n");
        out.write(Integer.toString(DateSystem.day));
        out.write("\n");
        out.write(Integer.toString(DateSystem.month));
        out.write("\n");
        out.write(Integer.toString(DateSystem.year));
        out.write("\n");
        for(int i = 0; i <= InventorySystem.drugsOwned.size(); i++)
            out.write(Integer.toString(InventorySystem.drugsOwned.get(i))+"\n");
        for(int i = 0; i <= AttributeSystem.attributeNames.length; i++)
            out.write(Integer.toString(AttributeSystem.attributeValues.get(i)) + "\n");



    } 
    catch (Throwable e) {} 
    finally 
    {
       try
       {
          if (out != null)
               out.close();
       } 
       catch (IOException e) {}
    }

My problem is that after the for loop for the inventory system.drugsowned nothing else gets wrote to file. So in this example AttributeSystem.attributeValues doesnt get wrote. I have also tried putting other things to be wrote after this loop including non loop things and they also haven't wrote. Whagwaan?

Maybe it's throwing an exception, which you're completely ignoring as if it didn't happen? Don't do that... — Jon Skeet, Jan 06 '12 at 19:51
You should put some logging in the exception blocks. Probably there were some exceptions thrown before/during writing the attributes. — evanwong, Jan 06 '12 at 19:52

Jon Skeet · Answer 1 · 2012-01-06T20:09:48.710

7

This is the problem:

for(int i = 0; i <= InventorySystem.drugsOwned.size(); i++)
    out.write(Integer.toString(InventorySystem.drugsOwned.get(i))+"\n");

The <= should be a <. So if there are 5 items in the collection, you're asking for element 5, which is the 6th element as the index is 0-based. That will throw an exception.

That's then getting masked by this:

catch (Throwable e)
{
}

You're completely hosing yourself here in terms of diagnostics:

Unless you can really handle an exception, don't catch it - or catch it and then rethrow it after logging (or whatever)
Catch specific exceptions wherever you can. (Catching Exception is bad; catching Throwable is worse.)
Silently catching without even logging is a terrible idea. That means you have no idea how often you've got problems, or what they were.

(Additionally, the code suggests you're either overusing static variables, or you need to sort out your naming conventions. That's a different matter though.)

edited Jan 06 '12 at 20:09

answered Jan 06 '12 at 19:52

Jon Skeet

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"You are completely hosing yourself" is right on the money. Empty catch block is almost always incorrect. – Bob Kuhar Jan 06 '12 at 19:55
Thanks for quick and useful response. To be honest i only have a vague idea of how try/catch blocks work, so ill take your advice and rework it. Should i just remove the try/catch entirely? – andy07070 Jan 06 '12 at 19:58
@Jon. Can you modify language in a first bullet. I think you've meant to say "don't catch it - rethrow it". Otherwise, a really nice exception handling tutorial in 3 lines :). – Alexander Pogrebnyak Jan 06 '12 at 19:58
Also with the static variable thing yeh i am using loads of those, what's the problem with using them? – andy07070 Jan 06 '12 at 20:03
@andy07070: They're basically global variables, leading to poor object orientation, poor testability, concurrency nightmares etc... – Jon Skeet Jan 06 '12 at 20:10

Java buffered writer wont write all data

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