Browse questions answered by Jon Skeet

How does jvm resolve call to overloaded method in this case?

Following code was successfully compiled class Overloading{ public static void aMethod (double val1, long val2) { System.out.println ("double, long"); } ...

Firstly, the JVM doesn't resolve overloads - the compiler does. (Whereas the JVM decided which overridden method to execute, for example.) As for why the method call becomes ambiguous - the compiler is looking for a single method where... more 6/28/2014 11:38:44 AM

java.util.regex.PatternSyntaxException: Unclosed character class near index 0

I am trying to replace all square brackets i my string . This is my program package com; import java.util.ArrayList; import org.apache.commons.lang3.StringUtils; import...

String.replaceAll takes a regular expression pattern, but you don't need regular expressions at all. You can use: str = str.replace("[", "").replace("]", ""); Or you could use a regex if you wanted, replacing both in one go: str =... more 6/28/2014 8:42:20 AM

Go SHA 256 hash differs from Java SHA 256 hash

If I generate the SHA-256 hash in the language "GO", I get a different byte-Array compared to the Java equivalent. This is the GO...

Why are they different? They're not, really. They're the same bits. It's just that Java doesn't have unsigned bytes - so any byte with the top bit set is negative. In every case like that, you'll see that Java result = Go result -... more 6/27/2014 10:28:50 PM

casting a byte array stored in a string to a byte array

I am being passed a byte array representing a pdf as part of an xml node. the byte array int the xml looks like this...

If you've got binary data within an XML document, I would hope that it's base64-encoded. Text data and binary data are different, and you shouldn't be trying to store arbitrary binary data in a string directly. If it is, you can just... more 6/27/2014 6:59:42 PM

Combine list<object> and list<otherobject> into single flat list

I have an object that has a member of a list of another object. i.e: public class ObjA { public int Id { get; set; } Other members.... public List<ObjB> ObjBs{...

Well it'll have to be just a List<object>, but this should work: // Flat list of ObjB var referenced = listA.SelectMany(x => x.ObjBs); // Concatenate listA with the flat list of ObjB var flat =... more 6/27/2014 2:52:34 PM

Avoiding code duplication when overriding abstract methods in enum

I am implementing a state machine in enum in Java. I have a toy example below, where I transition between X,Y and Z states based on group membership. The issue is, the transition...

Given that your logic is identical except for the value in the transition rule, you can just parameterize by that: enum Element { X(Group.A, Group.B), Y(Group.B, Group.A), Z(Group.C, Group.A); private final Group group; ... more 6/27/2014 1:58:36 PM

String to Date conversion is losing time

Does anyone know why Date is losing time values when converting from String ? I cannot seem to figure this one out. Here is what type of SimpleDateFormat I am using: ...

You've specified HH in your format, which is the 24-hour format. But you've also got an AM/PM designator. As such, "03:00 PM" doesn't make sense - it's simultaneously trying to represent 3am (03 in 24 hours) and 3pm (PM in the data). It... more 6/27/2014 1:23:28 PM

How to pass an argument when invoking a method (reflection)?

I need to call a method, passing an int. using the following code I can fetch the method but not passing the argument. How to fix it? dynamic obj; obj =...

The new object[1] part is how you're specifying the arguments - but you're just passing in an array with a single null reference. You want: int id = ...; // Whatever you want the value to be object[] args = new object[] { id... more 6/27/2014 1:10:30 PM

Joda Time, How to pick up format for string parsing?

Following code using Joda-Time library Long timestamp = DateTime.parse(dateInString,DateTimeFormat.shortTime()).getMillis(); generates: java.lang.IllegalArgumentException:...

Build a DateTimeFormatter matching your pattern, and use that. Your pattern certainly isn't a "short time" pattern, given that you've got a date in there as well... For example: // Possibly MM.dd.yyyy - we don't know what 12.05.2014 is... more 6/27/2014 12:50:20 PM

C# out struct parameter

I have this code in C# but I have a problem whit this code: struct myStruct { public string sOne; public string sTwo; } public static int ChangeStruct(out myStruct[]...

This has nothing to do with it being an out parameter, or an array. You'd get the same error with: public static void ChangeStruct(myStruct foo) Your method is public, but your struct is internal (the default accessibility for any... more 6/27/2014 11:00:01 AM