What is the best way to set empty array for properties in class Java? [duplicate]

Question

I have a class like:

public class TemplateFileResponse {
    private String path;
    private List<FileView> children;
}

I want to create an instance and set children is empty array. so what is the best way to do it?

An array is one thing e.g. FileView[]. A List is another different thing. — Michael
– Michael, Commented Jan 2, 2020 at 17:16
See Oracle tutorial, docs.oracle.com/javase/tutorial/java/javaOO/initial.html — Michael
– Michael, Commented Jan 2, 2020 at 17:17
You can create like this private List<FileView> children = new ArrayList<>(); — PythonLearner
– PythonLearner, Commented Jan 2, 2020 at 17:18
TemplateFileResponse t = new TemplateFileResponse(); t.setChildren(new ArrayList<>()); — koding
– koding, Commented Jan 2, 2020 at 17:28

Michael · Accepted Answer · 2020-01-02 17:32:32Z

-1

You can create an empty list with the new operator:

public class TemplateFileResponse {
    private String path;
    private List<FileView> children = new ArrayList<>();
}

You may also want to initialize the path field, either in a constructor or inline, because otherwise it will be initialized to null by default.

I suggest that you read a tutorial about Java classes, constructors, methods, and instantiating objects to understand how all of this works.

Michael

44.5k12 gold badges97 silver badges143 bronze badges

answered Jan 2, 2020 at 17:17

Code-Apprentice

84k26 gold badges162 silver badges289 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

@Michael I'm not confused. My wording is just poor and incomplete. Presumably inline intialization for path doesn't make any sense.

@Michael Sure, the path field could be left uninitialized at all. But then there would be no point in having it.

@Michael Feel free to write your own answer or make edit suggestions directly.

Alright, I have