static variable declaration in class java

Question

Why is this declaration wrong? This declaration leads to identifier expected error

class Abc{
    static ArrayList<Integer> p;
    p = new ArrayList<Integer>(); // identifier expected error
}

or just do it like this: static ArrayList p = new ArrayList(); .. better would be to code to interfaces and use the more up to date way to work with generics: static List p = new ArrayList<>(); — Stultuske, Feb 16 '18 at 09:11
"Why is this declaration wrong?" `p = new ArrayList();` is not declaration, it is *initialization*. — Pshemo, Feb 16 '18 at 09:14

score 2 · Accepted Answer · answered Feb 16 '18 at 09:16

You have a freestanding assignment statement in your class body. You can't have step-by-step code there, it has to be within something (an initializer block, a method, a constructor, ...). In your specific case, you can:

Put that on the declaration as an initializer

static ArrayList<Integer> p = new ArrayList<>();

Wrap it in a static initialization block

static {
    p = new ArrayList<Integer>();
}

More in the tutorial on initializing fields.

score 0 · Answer 2 · edited Feb 16 '18 at 09:41

0

This is the right way to do it :

import java.util.ArrayList;

public class Abc {
    static ArrayList<Integer> p;
    static {    
        p = new ArrayList<Integer>(); // works
    } 
}

edited Feb 16 '18 at 09:41

ibenjelloun

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answered Feb 16 '18 at 09:16

RCInd

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that's a working way to do it, plenty of possible improvements though. – Stultuske Feb 16 '18 at 09:23
true. the code pasted is erroneous. what i meant was that this the correct syntax (braces) – RCInd Feb 16 '18 at 09:29

static variable declaration in class java

2 Answers2