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Why is a ConcurrentModificationException thrown and how to debug it
...his will throw a ConcurrentModificationException when the it.hasNext() is called the second time.
The correct approach would be
Iterator it = map.entrySet().iterator();
while (it.hasNext())
{
Entry item = it.next();
it.remove();
}
Assuming this iterator supports the remo...
Set value to NULL in MySQL
... can be inserted/updated without quotes:
INSERT INTO user (name, something_optional) VALUES ("Joe", NULL);
UPDATE user SET something_optional = NULL;
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Advantages of std::for_each over for loop
...
The nice thing with C++11 (previously called C++0x), is that this tiresome debate will be settled.
I mean, no one in their right mind, who wants to iterate over a whole collection, will still use this
for(auto it = collection.begin(); it != collection.end() ; ++...
How do I force Postgres to use a particular index?
...of why and what you can do instead can be found here. The reasons are basically that it's a performance hack that tends to cause more problems later down the line as your data changes, whereas PostgreSQL's optimizer can re-evaluate the plan based on the statistics. In other words, what might be a go...
Spring RestTemplate timeout
...
I finally got this working.
I think the fact that our project had two different versions of the commons-httpclient jar wasn't helping. Once I sorted that out I found you can do two things...
In code you can put the following:
...
Naming of ID columns in database tables
...e wrong records.
If you would like to use the USING syntax that some dbs allow, you cannot if you use ID.
If you use ID you can easily end up with a mistaken join if you happen to be copying the join syntax (don't tell me that no one ever does this!)and forget to change the alias in the join con...
How do you send a HEAD HTTP request in Python 2?
...rt urllib2
>>> class HeadRequest(urllib2.Request):
... def get_method(self):
... return "HEAD"
...
>>> response = urllib2.urlopen(HeadRequest("http://google.com/index.html"))
Headers are available via response.info() as before. Interestingly, you can find the URL th...
SQL- Ignore case while searching for a string
...
Use something like this -
SELECT DISTINCT COL_NAME FROM myTable WHERE UPPER(COL_NAME) LIKE UPPER('%PriceOrder%')
or
SELECT DISTINCT COL_NAME FROM myTable WHERE LOWER(COL_NAME) LIKE LOWER('%PriceOrder%')
...
How do I declare an array of weak references in Swift?
...T] {
return objects.flatMap { $0.object }
}
func contains(_ object: T) -> Bool {
return self.objects.contains(WeakObject(object: object))
}
func addObject(_ object: T) {
self.objects.formUnion([WeakObject(object: object)])
}
func addObjects(_ obj...
New self vs. new static
...the first method, whereas static is bound to the called class (also see get_called_class()).
class A {
public static function get_self() {
return new self();
}
public static function get_static() {
return new static();
}
}
class B extends A {}
echo get_class(B::ge...