All Questions

3
answers

Avoiding comparison "! = null" in Java

I work with Java and for countless times I have to do a test object != null on the object before accessing it to avoid NullPointerException However, I think this practice ends up making the code very ugly, dirty and hard to read....
asked on 06.02.2014 / 11:38
2
answers

Why does not polymorphism work with Generics?

When trying to compile the following code I got an error. import java.util.*; class Animal { } class Cachorro extends Animal { } public class TestePoli { public static void main(String[] args) { List<Animal> cachorros = new A...
asked on 10.03.2014 / 00:06
2
answers

What is the utility of the varchar (0) column type?

I saw a question about column length of type Varchar and I went to consult a book that I have and I came across the following statement: The maximum length should be a number between 0 to 255. What is the utility of the zero-length va...
asked on 21.03.2017 / 14:10
5
answers

How to swap the img src of a small image for a large image?

Information: I'm trying to make a simple photo gallery. I want to show the image clicked in large size in the center of the screen. (Clicar em 0.jpg e mostrar em uma outra div 0Large.jpg) Problem: With the code I have I can do t...
asked on 14.02.2014 / 01:09
2
answers

How to translate a website in PHP?

I'm making a simple website with just a few PHP pages. I would like this page to be translated into Portuguese and English . I already use the gettext function in python and I saw that in PHP the syntax is very similar. Code:...
asked on 15.05.2014 / 17:41
2
answers

What is an algorithm?

I'd like to know what algorithms are. I program in C, study C ++ and Python. In all the online courses I've done, I've heard of such an algorithm, but I do not know what it is.     
asked on 10.05.2015 / 12:08
2
answers

Meaning of?:? =?! ? =?! in a regex

In several regex I noticed some symbols that do not seem to be part of the catch but some kind of functionality. I would like to know the name or term of these symbols and what is the functionality of each one. ?: ?= ?! ?<= ?<!     
asked on 22.04.2014 / 16:06
1
answer

How does Spliterator work in Java 8?

In Java 8 (which was released in March 2014), there is a new interface called Spliterator . It has a similar purpose to the Iterator , but it is designed to perform iterations in parallel . However, even after reading a lot about this inter...
asked on 16.12.2013 / 05:30
1
answer

What is Ergonomics?

1) What does the concept or meaning of Ergonomics? 2) What characteristics should software have to be considered ergonomic?     
asked on 27.10.2014 / 14:15
2
answers

Difference between CROSS APPLY and OUTER APPLY?

What is the difference between CROSS APPLY and OUTER APPLY ? How do they work? In what situation can they be used? Would it be possible to show some examples?     
asked on 23.04.2014 / 18:38