How to Destroy an Object

how to destroy an object in java?

Answer E is correct answer. If E is not there, you will soon run out of memory (or) No correct answer.

Object should be unreachable to be eligible for GC. JVM will do multiple scans and moving objects from one generation to another generation to determine the eligibility of GC and frees the memory when the objects are not reachable.

destroy object of class python

Think of it that way: you're asking a class to self-destruct using an inner method, which is kind of like trying to eat your own mouth.

Luckily for you, Python features garbage collection, meaning your class will be automatically destroyed once all of its references have gone out of scope.

If you need to do something specific when the instance is being destroyed, you can still override __del__() which will kinda act like a destructor. Here's a silly example:

class SelfDestruct:
    def __init__(self):
        print("Hi! I'm being instanciated!")
    
    def __del__(self):
        print("I'm being automatically destroyed. Goodbye!")

    def do_stuff(self):
        print("I'm doing some stuff...")

Now, try instanciating this class in a local scope (such as a function):

def make_a_suicidal_class():
    my_suicidal_class = SelfDestruct()
    for i in range(5):
        my_suicidal_class.do_stuff()
    return None

Here, the lifespan of the object is bound by the function. Meaning it'll be automatically destroyed once the call is completed. Thus the output should look like:

>>> make_suicidal_class()
"Hi! I'm being instanciated!"
"I'm doing some stuff..."
"I'm doing some stuff..."
"I'm doing some stuff..."
"I'm doing some stuff..."
"I'm doing some stuff..."
"I'm being automatically destroyed. Goodbye!"
>>>

If your class was instanciated in a global scope, then it won't be destroyed until your program ends.

Also, it should be noted that manually calling the __del__() destructor does NOT actually destroy the object. Doing this:

foo = SelfDestruct()
foo.__del__()
foo.do_stuff()

Results is this output:

"Hi! I'm being instanciated!"
"I'm being automatically destroyed. Goodbye!"
"I'm doing some stuff..."

ergo, the instance still has a pulse... If you really need to prevent the instance from being referenced again in the current scope, you have to call del foo to do so.

Though as previously stated, Python actually reference-counts classes and variables. So if your class object is used elsewere, invoking del foo will not actually release it from memory.

Here's an exhaustive explanation in the python docs
https://docs.python.org/2.5/ref/customization.html

"del x" doesn't directly call x.del() -- the former decrements the reference count for x by one, and the latter is only called when x's reference count reaches zero.

Long story short: Don't think about it! Let python deal with memory management. The whole point of garbage collection is to stop worrying about the lifespan of your variables!

how to destroy an object in C++

delete &b;

You may not do that. delete must only be used on pointers returned from allocating non-array new. You did not get &b from an allocating new-expression.

You could approach the problem from another direction: Since the number of objects doesn't change, it could be much simpler to think of the state of the object changing, instead of destroying and creating a new one. You could simply write a member function that resets the state of the object as desired:

if(b.collision) {
     b.reset_state();
}

That said, it is technically possible to destroy an automatic (or static) variable as long as you create a new one in its place (as is your intention).

The destruction is done by invoking the destructor, while the construction is done using a placement-new expression:

b.~line();
new(&b) line;

But this approach has more caveats than keeping the single object throughout.

How to destroy object in itself

Java objects live until there are no longer any references to them. Since an object cannot determine how many references there are to itself, an object cannot "destroy itself".

How to destroy a object when dragged into an empty canvas

Here is your answer.

https://answers.unity.com/questions/889220/unity-46-ui-canvas-width-height.html

Perhaps, you need to destroy an object, that is outside the player's camera? In this case, use the code Screen.width and .height

If you need to destroy an object, that is not included in the slot, then you need to create this area. There are many tutorials on the internet, like "how to create borders, around an area". Use one of them, what do you need in your case.

Separately from myself, I advise that it be smooth, with considering the size of the dragged object itself. So that it is not destroyed immediately, as it enters the field of destruction, but perhaps more smoothly, when last part of the object, has enter in that area. As an option, with the launch of the script, for a smooth destruction. (DOTween as an option, for different types of smoothness). Use IEnumerator, and like that multithreading in script, to control this process.

PHP - how to destroy object and objects it contains?

unset($mainObject); Will destroy object and memory will be free.

How to destroy a JavaScript object?

You could put all of your code under one namespace like this:

var namespace = {};

namespace.someClassObj = {};

delete namespace.someClassObj;

Using the delete keyword will delete the reference to the property, but on the low level the JavaScript garbage collector (GC) will get more information about which objects to be reclaimed.

You could also use Chrome Developer Tools to get a memory profile of your app, and which objects in your app are needing to be scaled down.