I got a question. Why this code prints YYZ10.0 instead of printing XXZ10.0? The first constructor is A(int), then inside statement it returns false, so 9+1f should jump into A(float) constructor but instead it is going to A(double). Answer If there are multiple overloads of a method, Java picks which one to call at compile time, not at run time.
Tag: constructor
Java Problem: Calculations in one subclass’ constructor affecting fields of another subclass’ instance
I have two abstract classes i.e. Medicine and Prescription. All code can be found at https://codeshare.io/aVAdr3 These two classes have subclasses, the class hierarchy diagram is as follows: and… …
Spring autowiring dependency with constructor arguments
I have created a service class, TestService whose constructor takes an array of Strings and has a little logic to return a list of Strings with length greater than 5. How do I get about injecting this into my Controller class with the array of Strings argument? Answer I think it is impossible. Instead inject String[] testStrings holder: However, in
Why any initialization or even print inside the constructor with @Tolerate lombok cannot be reached?
what is the problem with the constructor with @Tolerate of lombok, and why it cannot be reached? and how can I fix it? I wanna initialize a map by setting some default keys and values inside the constructor block, but it cannot be initialize because nothing can be reached inside the constructor. Would you please help me? thank you. OUTPUT:
super.a = b instead of super(b)
I’m learning the super keyword and accidentally get this, here’s an example : The usual way to do this as in the tutorials is super(b) to reusing its parent constructor, but what is wrong with super.a = b? Answer When you write your class A like this: you overwrite the default constructor and in the line this.a = a you
Spring boot error in Application.java package
hello I just created a project in spring boot initializer but when I import the project in sts I have a set of errors that I do not understand the errors are : The type java.lang.Class cannot be resolved. It is indirectly referenced from required .class files Implicit super constructor Object() is undefined for default constructor. Must define an explicit
Shorthand class constructor member initialisation
Writing simple constructors in Java is pretty verbose. For each field that needs to be initialised you need to write the variable name four times, e.g. like so: Is there a shorthand for that like e.g. in Kotlin? This question was asked before here: Shorthand class constructor field initialisation But that was way back in 2013 (6 Java versions ago)
Is there a Lombok way to initialise a final field that is calculated from other fields?
I’m using Lombok to minimize code. Here’s my (contrived) situation in vanilla Java: I want to use lombok to generate the constructor and getters: To get the computation into the class, you might consider an instance block: but instance blocks are executed before code in the constructor executes, so x won’t be initialized yet. Is there a way to execute
multiple constructors for final fields in java
I have some final fields in the class like But this gives an error that final field ‘b’ might not have been initialized. So any help would be appreciated on how to handle final attributes initialization in case of multiple constructors. It works fine if I have only the second constructor. Answer You can initialize b to default false. All
Behavior of costructors in sub classes in Java
let’s say I have the following code: What are the outputs when I try to execute I thought it would first call the constructor of B and the constructor of B will call the constructor of A but the I don’t know which between “creating A” or “Hi” message will be shown first. The first thing invoked on a class