Browse questions answered by Jon Skeet

Reading a file using fixed number of bytes java

I am writing a program to copy large files, so I want to read specific number of bytes and write to another file. I want to copy the file and get same number of bytes. But I am...

There are several problems with your code: You're using the default platform encoding to convert the binary data into text (by calling new String(byte[]) instead of specifying an encoding You're using the default platform encoding to... more 2/15/2015 10:07:41 AM

What is the size of a boolean In C#? Does it really take 4 bytes?

I have two structs with arrays of bytes and booleans: using System.Runtime.InteropServices; [StructLayout(LayoutKind.Sequential, Pack = 4)] struct struct1 { ...

Firstly, this is only the size for interop. It doesn't represent the size in managed code of the array. That's 1 byte per bool - at least on my machine. You can test it for yourself with this code: using System; class Program { ... more 2/14/2015 10:01:41 AM

Use string as argument for GetValue()

I have a class Player, and an instance of that class called player. Inside that class, I have an auto-property called Name. I need to access the property Name from the instance....

Instances don't have names, generally. (You can create a class with a Name property, but that's nothing the framework is going to care about.) The value you have to pass to PropertyInfo.GetValue is a reference to the object whose property... more 2/14/2015 9:39:39 AM

Seeking better dictionary initialization

I recently answered a question here with a PowerShell dictionary that used "ContainsKey" to decide whether to define a key value or add to it if necessary. I do that a lot -...

ConcurrentDictionary in .NET will allow you to do that, yes: sums.AddOrUpdate(key, value, (k, v) => v + value); You should be able to use that (with syntax changes, obviously) in PowerShell, too. Alternatively, if you want to do... more 2/14/2015 8:06:42 AM

java.sql.Date (YYYY MM DD) to java.util.Date (DD MMM YYYY) conversion

Need advise how to send the java.sql.Date (YYYY-MM-DD) to java.util.Date (DD-MMM-YYYY). The class java.sql.Date is designed to carry only a date. I have a table with column...

I want to send the output in DD-MMM-YYYY format to the JSP page view. Then you need to use a SimpleDateFormat to do so. Currently you're using the result of Date.toString(), and ignoring temp which should already have the right... more 2/13/2015 5:48:30 PM

Java SimpleDateFormat unexpected parsing behaviour

I'm reading information from a file (.csv) that will be inserted to a database after validation and approval from the end user. The text file is read, validated and its...

No, it "becomes" a java.util.Date value. If you're then converting it back to a string by calling Date.toString(), you should consult the Date.toString() documentation for what to expect. The value stored in the Date is just a point in... more 2/13/2015 5:29:37 PM

Recommend best constructor with attribute?

Is there a way to denote the best constructor to use in C#, so that a developer knows which to pick by default? Say you have a class: public class MyClass { public...

Firstly, I'd advise you to chain your constructors the other way round - make the ones with fewer parameters chain (possibly indirectly) to a single constructor with all the parameters, and make that the only one which sets anything. That... more 2/13/2015 5:14:26 PM

Java Vs C# Long to DateTime Conversion

In Java I have the following test that passes fine // 42 bits of time is good enough for the next 100 years. // An IEEE double has 52 bits of mantissa, so our dates can be easily...

Your test is basically confusing ticks with milliseconds. If you only need to store a number of milliseconds since the unix epoch, then do so - but I'd recommend using something like this to perform the conversion: public static readonly... more 2/13/2015 4:40:25 PM

What is advisable to defer the checking an IllegalArgumentException?

Consider an example, of adding two hex numbers represented as char array: eg: 2A and 1D. Now, A upto F are valid, but G-Z are invalid for 16 bits. I have two cases below to throw...

In this case, there's no real harm done in terms of the behaviour due to checking later - it's not like the code which has executed so far in the method will have had an observable impact. You'll have wasted a small amount of time, but... more 2/13/2015 4:14:33 PM

LINQ statement needs to be optimized

I have the following code var x = from e in db.Employees where e.id == 746 join f in db.CoWorker on e.CoWorkerID equals f.ID into fa from fr in fa.DefaultIfEmpty() ...

Here's a query which performs the concatenation client-side instead. As you can see, it's more long-winded - you should absolutely check that it makes a significant difference before you decide to embrace it: var dbQuery = from e in... more 2/13/2015 2:25:43 PM