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GetType() can lie?
... and polymorphism and reading Eric Lippert's answer, I started thinking if making GetType() not be virtual really ensured that an object could not lie about its Type .
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java.net.ConnectException: localhost/127.0.0.1:8080 - Connection refused
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Since you have not specified you are connected to a server from the device or emulator so I guess you are using your application in the emulator.
If you are referring your localhost on your system from the Android emulator then you have to use htt...
Alter a MySQL column to be AUTO_INCREMENT
I’m trying to modify a table to make its primary key column AUTO_INCREMENT after the fact. I have tried the following SQL, but got a syntax error notification.
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Do I need to convert .CER to .CRT for Apache SSL certificates? If so, how?
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File extensions for cryptographic certificates aren't really as standardized as you'd expect. Windows by default treats double-clicking a .crt file as a request to import the certificate into the Windows Root Certificate store, but treats a .cer file as a request...
Use dynamic (variable) string as regex pattern in JavaScript
...reate the regex from a string, you have to use JavaScript's RegExp object.
If you also want to match/replace more than one time, then you must add the g (global match) flag. Here's an example:
var stringToGoIntoTheRegex = "abc";
var regex = new RegExp("#" + stringToGoIntoTheRegex + "#", "g");
// at ...
What are the differences between B trees and B+ trees?
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The image below helps show the differences between B+ trees and B trees.
Advantages of B+ trees:
Because B+ trees don't have data associated with interior nodes, more keys can fit on a page of memory. Therefore, it will require fewer cache misses in orde...
What's the nearest substitute for a function pointer in Java?
...irst you have to define an interface with the function as its only member, if you can't reuse an existing one.
interface StringFunction {
int func(String param);
}
A method that takes the pointer would just accept StringFunction instance like so:
public void takingMethod(StringFunction sf) {...
Comparing HTTP and FTP for transferring files
...for request-response of small files, but FTP may be better for large files if tuned properly. FTP used to be generally considered faster. FTP requires a control channel and state be maintained besides the TCP state but HTTP does not. There are 6 packet transfers before data starts transferring in...
How to convert String to long in Java?
...tic void main (String[] args) {
// String s = "fred"; // do this if you want an exception
String s = "100";
try {
long l = Long.parseLong(s);
System.out.println("long l = " + l);
} catch (NumberFormatException nfe) {
System.out.println("Number...
SQL Joins Vs SQL Subqueries (Performance)?
I wish to know if I have a join query something like this -
8 Answers
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