Error adding to ArrayList - Java

Question

This is a snippet of my code:

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

public class Spiral3{
    public static ArrayList<Integer> R = new ArrayList<Integer>(); 
    public static ArrayList<Integer> K = new ArrayList<Integer>();
    R.add(1);
    K.add(1);
    public static String pekare = "H";

All I'm trying to do here is create two arrays with the first element int 1. So R = [1], K = [1]. I get the following error:

Spiral3.java:8: error: <identifier> expected
    R.add(1);
         ^
Spiral3.java:8: error: illegal start of type
    R.add(1);
          ^
Spiral3.java:9: error: <identifier> expected
    K.add(1);
         ^
Spiral3.java:9: error: illegal start of type
    K.add(1);

What's going on here? Thankful for your help :)

Eran · Accepted Answer · 2015-03-29 20:00:26Z

2

R.add(1);
K.add(1);

These statements should be inside some method or constructor or initializer block.

For example :

static {
    R.add(1);
    K.add(1);
}

edited Mar 29, 2015 at 20:00

answered Mar 29, 2015 at 19:57

Eran

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2 Comments

Sahand Over a year ago

Could I possibly add them in the initialization to avoid having to add them inside a method?

Eran Over a year ago

@user3128156 You can use a static initializer block (see my edit).

Rohit Jain · Accepted Answer · 2015-03-29 20:02:15Z

2

If you want the list to be initialized to those values, you can pass it as List:

public static ArrayList<Integer> R = new ArrayList<Integer>(Arrays.asList(1)); 
public static ArrayList<Integer> K = new ArrayList<Integer>(Arrays.asList(1));

answered Mar 29, 2015 at 20:02

Rohit Jain

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Comments

ozanonurtek · Accepted Answer · 2015-03-29 20:07:33Z

0

You should do like this;

  // create an array list
  ArrayList al = new ArrayList();

  System.out.println("Initial size of al: " + al.size());

  // add elements to the array list
  al.add("C");
  al.add("A");
  al.add("E");

answered Mar 29, 2015 at 20:07

ozanonurtek

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