NeedHelp Debugging: Append two ArrayLists using Method - Java

Question

Write a method public static ArrayList append(ArrayLista, ArrayList b) that appends one array list after another. For example, if a is 1 4 9 16 and b is 9 7 4 9 11 then append returns the array list 1 4 9 16 9 7 4 9 11. This is what I have done so far and I'm pretty sure I'm almost finished but I keep running into errors; mainly "cannot find symbol ArrayList" Can anyone help me?

import java.util.Arrays;

public class AlAppend { 

public static ArrayList<Integer> append(ArrayList<Integer> a, ArrayList<Integer> b) {
ArrayList<Integer> c = new ArrayList<Integer>();
c.addAll(a);
c.addAll(b);
return c;   
}

public static void main(String[] args) {

    // List 1
    ArrayList<Integer> array1 = new ArrayList<Integer>();
        array1.add(1);
        array1.add(4);
        array1.add(9);
        array1.add(16);
    System.out.println("List 1: " + array1);

    // List 2
    ArrayList<Integer> array2 = new ArrayList<Integer>();
        array2.add(9);
        array2.add(7);
        array2.add(4);
        array2.add(9);
        array2.add(11);
    System.out.println("List 2: " + array2);

    // Combined List
    ArrayList<Integer> array3 = append(array1, array2);
    System.out.println("Combined: " + array3);
}

}

libik · Accepted Answer · 2014-03-12 23:20:46Z

1

Step 1)

Just change this :

c.add(a);
c.add(b);

to this :

c.addAll(a);
c.addAll(b);

PS : Next time you post question, please copy the error message, statement "keep getting into errors" is facepalm statement in programming community :).

Step 2)

Add line to the top :

import java.util.ArrayList;

Step 3)

Download netbeans, it is very user-friendly and it helps you solve errors by "tip" or even solving dependencies (like imports) for you.

edited Mar 12, 2014 at 23:20

answered Mar 12, 2014 at 23:03

libik

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1 Comment

Sjanes227 Over a year ago

I appreciate the help! I've got 10 errors left, most of them being; it cannot find the symbol ArrayList<Integer>

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