BankAccount.java Test.java I should get number of accounts is 3 but I’m getting 4. If I instantiate all accounts with the parametrized constuctor, I get 3. If I add BankAccount account4 = new BankAccount();, I get 6. Is the default constructor called twice? Answer This is your problem: The explicit call…
Tag: constructor
Why does super() not get called in the other constuctor?
If both House() and House(name) are called then why is not “Building” printed two times, but instead one time? Output: Answer House(String name) calls this() which is the same as House(). House() implicitly calls super() which is the same as Building(). You never call Building(String name). House(…
Is it technically possible to derive a class that only has a private constructor in Java?
I found a lot of answers about it on this site, but most of them are based on modifying the requirements or modifying the code of the parent class to do so. Without discussing the requirements and modifying the code of the parent class, can we get its constructor and derive it through reflection and other mea…
How to call a method from a class given that I have the Constructor for it?
If I have a constructor object Constructor<?> productConstructor, how can I call the run() method that exists in that class? For example, let’s say I have the class: I can run the constructor for my class like this: If I keep the code as is, then I have to place the run() method inside of the cons…
Java, my own copy() method would not work
I am learning java and came upon a small problem, my copy() method will not work. I work based on a UML diagram and I am pretty sure that I’m doing everything correctly. Here is the code: Constructor: copy() method: The error flashes at the parantheses FileName() it says: ‘FileName(java.lang.Strin…
How to call a method from a class that contains a constructor?
I recently learned that calling a class that contains a constructor means that it will call the constructor only, but what if I want to call a method from that class in Main? Let’s say I have a class that looks like this And in Main, I want to create an instance of Student and call showDetails(), howeve…
Since when have enum constructors’ default access modifier been private?
How long have enum constructors’ default access modifier been “private”? Since the beginning or did it change in Java 8? If it did, then what was the default access modifier of a constructor declaration with no access modifier? (I’m guessing it is the default(package accessible) like o…
How can I accept an argument list in a constructor and add it to a collection in Java?
I’m trying to make a constructor that would accept any number of variables of class “Item” as a variable argument list and add them to appropriate collection. What would be the best way to go about it? My code so far: Answer Item… args should be fine.. You can then just do this … inste…
How can I make my program run the validation code in my sub-class rather than the parent class?
As the title suggests, I was wondering if there was a way to make my program execute the validation code in the constructor of my sub-class, instead of the validation code in the constructor in my parent class? Here is a very basic example: Here I have the constructor of my Teacher class, which throws an exce…
How to create objects for parameterized constructors in Java, when we have two classes with the same attributes?
I have class Student, that has first name, last name and age, and a method to print the name and the age of the student. And I have a second class Professor, that has first name, last name, and university. And I have a method to print the info about the professor. And in the main class I create two