Browse questions answered by Jon Skeet

Why first enumeration of encrypting data takes so long

I want to create performance test where I am encrypting data using AES with PKCPadding5/7 depends on provider(IBM or BouncyCastle) on aix system. My question is why first...

Revised answer There's time taken to load and JIT-compile the code on the first call - that's why typically benchmarks don't include the first run. (In fact, many JVMs re-JIT more and more aggressively, so the performance improves over... more 4/1/2014 1:59:01 PM

Overcoming generics put get rule

I have read about the generics get and put rule that should prevent you from adding a Banana to a List<? extends Fruit>: public abstract class Fruit { } public class Banana...

No, it's absolutely fine to have two different kinds of Fruit in a List<Fruit>. The issue comes when you've actually created a List<Banana>. For example: List<Banana> bananas = new ArrayList<>(); bananas.add(new... more 4/1/2014 1:15:39 PM

Improper output of the following String programs

public class NoOfConsAlphabet { public static void main(String[] args) { String str="aaabbddaabbcc"; int count=1; String finalString=""; for(int...

This is the problem: str.charAt(i)+count+"," That's performing a char + int conversion, which is just integer arithmetic, because + is left-associative. The resulting integer is then converted to a string when "," is concatenated with... more 4/1/2014 12:30:33 PM

Java enum custom names

I want to have a Java enum whose values are integers. For example: public enum TaskStatus { TaskCreated(1), TaskDeleted(2) } But I also want custom names for...

Just add a field for that: public enum TaskStatus { TaskCreated(1, "Task Created"), TaskDeleted(2, "Task Deleted"); private final int value; private final String description; private TaskStatus(int value, String... more 4/1/2014 11:37:13 AM

why variable defined in a class is not a local variable but instance variable in java?

According to the doc Local variables in java are declared in methods, constructors, or blocks. In the below Class A isn't x a local variable too since it is in blocks({}) i know...

In the below Class A isn't x a local variable too since it is in blocks({}) No. It's not in a block. It's in a class declaration, but that's not a block as such. "Block" isn't synonymous with "text in braces". To be a bit clearer,... more 4/1/2014 8:19:19 AM

XmlDocument file name with space

I have XML file that contains services names in windows7, one of the services has white space i.e "service name" I get exception when I load the file: fileName = file; pathToFile...

The problem has nothing to do with the name of the XML file, or the code you posted. It has everything to do with the XML being invalid. XML element names can't contain spaces, so this isn't valid: <Service-1 Agent/> Instead, you... more 4/1/2014 7:47:52 AM

How to add xmlns attribute to the root element?

I have to write xml file like the fallowing <VersioningConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"> ...

LINQ to XML makes this trivial - you just specify the namespace for the element, and it will include the xmlns="..." automatically. You can give it an alias, but that's slightly harder. To produce the exact document you've shown, you just... more 4/1/2014 6:14:51 AM