Dont understand something

so we are assigning a "new Date" to the variable "currentTime" of the type Date? We are making the variable refer to a new object that we create during the instansiation?

You got it Aditya!

We are assigning a "new Date" to the variable "currentTime". Therefore, currentTime is of the type Date. And yes, this variable is being set to the object we made when we instantiated it (The moment in time when we give currentTime a value).

Just to give a bit more sense to this, we call it instantiating because we can have multiple, different Date classes at a time. It would be a pain if whenever we instantiated a new Date object, all of the other dates were set to the same moment in time. Therefore, we can have multiple instances of a class, and each Date object can have its own unique time.

Great work :)

1) What do we mean when we add the "346346234667L" in "new Date(346346234667L)" ?

2) I don't understand this part-' thing to note is that the time does not automatically change. If you initialized the date/time and logged it to the console 10 seconds later, the time printed would be 10 seconds early.'

Hey again Aditya,

Not sure where you got the 3463... number from, but I believe it would be a time in UNIX that you're talking about.

For example, in this video when Craig creates a Date using a similar number (1421...), he uses what's called a UNIX Timestamp.

Basically, a UNIX timestamp counts the number of seconds that have passed since January 1st, 1970, 00:00:00GMT, and uses this to work out the date. So, at the time of writing, 1472916935 seconds have passed since that time, and that corresponds to 03 September 4:35PM GMT

Now, the idea that the time does not change dynamically is quite important to understand the language of Java.

When we initialize the time using new Date(), it gets the UNIX time of this current moment in time. However, that number doesn't just continue ticking up in seconds. So, here's an example to better understand this:

long currentTime = new Date();
// The time when this code runs is 1472916935.
console.log(currentTime); // Outputs 1472916935.

Thread.sleep(10 * 1000); // Pause code execution for 10 seconds.
console.log(currentTime); // Outputs 1472916935.

So, as you can see, the currentTime is still the same! Huh. How would we get around this? Well, we'd need to call Date's constructor for a second time, and get a new Date object returned back:

currentTime = new Date();
// The time when this code runs is 1472916945.
console.log(currentTime); // Outputs 1472916945.

Now, we've called the Date() constructor for a second time, and it's returned the up-to-date date/time so that we can output it.

Hopefully this explains things but if you still don't fully understand, let me know :)

oh..but I have 3 more questions :p -

1) How does the instantiation of the class Date, set it equal to the current date? Is it because of some code in the constructor?

2) When we write "new Date" then we set the date object equal to the time when the program was compiled, or when the user posted the forum post, and there is an automatically number generated in the pranthesis()?

3) When we give a number in the paranthesis as an argument, like "new Date(564564757567L)" then will it work out a date using the same method? Just this time, the date would be pre feeded and not the current date, right?

Hey again Aditya,

For your first question, you're correct - it is because of some code in the constructor. This code gets the current time, and then returns it as a long in the constructor.

When we pass in a date to the constructor, it will run a constructor that can handle this date, and store it in the Date object created. Note that if we did new Date() with 0 arguments, it uses a different constructor that gets the current time instead. Also, this is the runtime (The time this line of code is run in program) - not the compile time.

This should also answer your last question but just to reiterate; yes, passing an argument causes a different constructor to run that can handle the argument, and that will use the time we pass as the argument.

Hope it helps and if there's anything else, give me a shout :)

when we declare "new Date()" in our program, it will feed the current time when the program runs. When we use "new Date()" in an input-output base program it will feed the time when the user inputted the data and when we use "new Date()" in an if statement, it will feed the time when the statement was true, right?

Hey again Aditya,

The Date is created whenever that specific line of code is executed. So, if this is inside an if statement, it would be when it is true, as that is when the code gets executed. This applies for all of the examples you have stated - whenever the line of code is executed is when the Date gets set :)

So, yes, if you did have an i/o system, you would wait for the input and if the input triggers a new Date object to be created, then the date would be set to the time of input.

oh, ok thanks :D