Browse questions answered by Jon Skeet

Is there any advantage to declaring a class static in C#?

In C#, you can declare a class as static, which requires all members to also be static. Is there any advantage (e.g. performance) to be gained by doing so? Or is it only a matter...

Or is it only a matter of making sure you don't accidentally declare instance members in your class? It's that, but it's more than that: It prevents instantiation by not having an instance constructor at all (whereas all other... more 3/8/2014 9:00:24 AM

How to get the current date format of Android emulator

I want to get the current Date Format of Android emulator. Can anyone help me? Not like this SimpleDateFormat FormattedDATE = new SimpleDateFormat("M-d-yyyy"); Calendar...

There are various options: DateFormat defaultFormat = DateFormat.getDateInstance(); DateFormat longFormat = DateFormat.getDateInstance(DateFormat.LONG); DateFormat mediumFormat = DateFormat.getDateInstance(DateFormat.MEDIUM); // etc And... more 3/8/2014 8:05:13 AM

Index is outside bounds of array

When I run this it says that index was outside of bounds for the array but it is not. If I change public static ConectorRec[] ch = new ConectorRec[74]; to ConectorRec[] ch = new...

When I run this it says that index was outside of bounds for the array but it is not Yes it is. Even if I couldn't pinpoint the problem, I'd always bet on the runtime being more accurate than the developer's opinion on this... This... more 3/7/2014 6:33:49 PM

Reuse class / no references

Task: reuse C# code in different projects but without project referencing (don’t want extra dll/references just because of a small utility class). There’re 4 projects, one of them...

I wonder is there a way to source link files so that the class inside a file gets project-specific unique namespace… Well you could use preprocessor directives: #if PROJECT_FOO namespace Foo #elif PROJECT_BAR namespace Bar #elif... more 3/7/2014 6:32:21 PM

Calculate time between the current time and a certain day

I am fairly new to (Java) programming and I am trying to build a little Android app that will tell you if it's already weekend or not. I already got it so far that it can tell...

Here's the process, but as a description rather than code, leaving the rest for you as an implementation exercise: Get the current time in milliseconds, and remember it for later Create an appropriate Calendar object Work out the day... more 3/7/2014 6:14:28 PM

how to convert from image to short string?

I use Base64 system for encode from image to string this code Bitmap bitmap = BitmapFactory.decodeFile(picturePath); ByteArrayOutputStream stream = new...

You can't. Images typically contain a lot of data. When you convert that to text as base64 it becomes even bigger (4 characters for every 3 bytes). So yes, that will typically be very long if it's a large image. You could compress the... more 3/7/2014 4:49:33 PM

Why can I use the shorthand `[Authorize]` instead of the name of the actual class, `[AuthorizeAttribute]`?

I am browsing through the ASP.NET web stack source code and noticed that the AuthorizateAttribute class is actually named as such (see here). So, why is it that I can use...

The C# compiler automatically tries appending the suffix Attribute when you're using an attribute (which is obvious syntactically). It just makes things easier. From the C# 5 spec section 17.2 (Attribute Specification): By convention,... more 3/7/2014 4:39:11 PM

Strange java behavior of wait/notify

I've found strange behavior of java concurrency. See on the next code below: public class Test { static CountDownLatch latch = new CountDownLatch(1); public...

It's because you're waiting on a Thread instance. Thread uses wait/notify/notifyAll internally, so you shouldn't do that yourself as well - you'll confuse Thread, and Thread will confuse you. In particular, when a thread exits, it calls... more 3/7/2014 4:07:22 PM

Methods and Strings

I am new to Java programming. My homework problem states that to Write a program that calls a method to print the number of vowels in a sentence (use ‘nextLine()’to read a...

The problem is with your method declaration. You need to declare the type of your str parameter, like this: public static String vowel(String str) Additionally, you're only declaring str2 within your loop - so you can't use it for the... more 3/7/2014 1:03:46 PM

Assigning a number to a text block

I want to set the Text of a TextBlock according to the Value of a Random Number I thought about using toString for getting the String of the Random number and then assigning it...

The problem is that you're not calling the ToString method. In this statement: num1.Text = Number1.ToString; ... ToString is a method group, which can be used for conversions to delegate types. So for example, this is... more 3/7/2014 12:38:34 PM