Is there a faster/simpler way of constructing objects from scanned inputs

Imagine you want to create an unknown amount of instances of a class. You decide to use an ArrayList (if there is a better option I would very much appreciate if someone could explain this) You want to allow instances of the class to be created through the System Input.

import java.util.ArrayList;
import java.util.Scanner;

class MyClass {

	static ArrayList<MyClass> myArrayList = new ArrayList<>();
	int field1;
	int field2;
	int field3;

	public MyClass(int field1, int field2, int field3) {
	// contructor statements
	}

Here is the problem, if you scan inputs, you cannot feed them into the constructor, as you need to print messages in between and then scan the input. You are forced to store the values of all the fields by assigning them to other variables as shown below, you can also set the fields at the index of the new object each time you scan them, but this seems like it would be slow and complicated code.

	static void createNewInstance() {
	
	Scanner myScanner = new Scanner(System.in);

	System.out.println("Enter field 1");
	int f1 = myScanner.nextInt();
	System.out.println("Enter field 2");
	int f2 = myScanner.nextInt();
	System.out.println("Enter field 3");
	int f3 = myScanner.nextInt();

	myArrayList.add(new MyClass(f1, f2, f3));
	}
}

So I am wondering if there is a way to pass the scanned input directly into the constructor, it seems like storing the values as variables would take a bit of computation and also, if these variables are primitive, i think they would be in stack, which stack has static memory allocation, so they are permanently there. It seems to me like on a large scale, this is not such a great solution, but I am also extremely limited in my knowledge of program performance, so I am not exactly sure. I am guessing the answer is just use that solution, any others are just too complicated to be worth using. Thank you for reading, sorry I have struggled to word this question in a concise way.

In "normal" situation you will never create objects like this - there are many many ways the application receiving objects (reading from batch, receiving HTTP requests, deserialization...) and I never saw "on production" prompting the user "now give me the value of the first field..." etc and scanning values

> it seems like storing the values as variables would take a bit of computation

and that's not a problem at all - creating objects in Java is super fast, additional three primitive fields are not relevant at all when it comes to the performance

Don't overengineer this

Firstly, lets mention that Premature Optimization Is the Root of All Evil

Having mentioned that, if you still want to get your user input through the stdin, you could asks your user to provide his numbers at once.
e.g

"Provide your numbers seperated by ,"

And then, after using scanner.nextLine() you can split the line and get your numbers (and validate that all 3 numbers were given).

Builder pattern and optionally Project Lombok are your friends!

public static void main(String[] args) {
MyClass obj = createNewInstance();
}
public static MyClass createNewInstance() {
Scanner scan = new Scanner(System.in);
MyClass.MyClassBuilder builder = MyClass.builder();
builder.field1(scan.nextInt());
builder.field2(scan.nextInt());
builder.field3(scan.nextInt());
return builder.build();
}
@Builder
@RequiredArgsConstructor
public static class MyClass {
private final int field1;
private final int field2;
private final int field3;
}

Another option is to put Scanner directly to the constructor (but this is NOT GOOD from Object Design Principles)

public static void main(String[] args) {
MyClass obj = new MyClass(new Scanner(System.in));
}
public static class MyClass {
private final int field1;
private final int field2;
private final int field3;
public MyClass(Scanner scan) {
field1 = scan.nextInt();
field2 = scan.nextInt();
field3 = scan.nextInt();
}
}