arraylist java

1import java.util.ArrayList;

1   ArrayList<Integer> contractValue = new ArrayList<Integer>();

1List<String> words = new ArrayList<String>();

1ArrayList<String> al = new ArrayList<String>();
2      al.add("Hello");
3      al.add("Wor");
4      al.add("ld");
5      StringBuffer sb = new StringBuffer();
6      
7      for (String s : al) {
8         sb.append(s);
9         sb.append(" ");
10      }
11      String str = sb.toString();
12      System.out.println(str);//"Hello wor ld" 

1import java.util.ArrayList;
2public class ArrayListExample
3{
4   public static void main(String[] args)
5   {
6      int num = 14;
7      // declaring ArrayList with initial size num
8      ArrayList<Integer> al = new ArrayList<Integer>(num);
9      // append new element at the end of list
10      for(int a = 1; a <= num; a++)
11      {
12         al.add(a);
13      }
14      System.out.println(al);
15      // remove element at index 7
16      al.remove(7);
17      // print ArrayList after deletion
18      System.out.println(al);
19      // print elements one by one
20      for(int a = 0; a < al.size(); a++)
21      {
22         System.out.print(al.get(a) + " ");
23      }
24   }
25}

1//requires either one of these two imports, both work.
2import java.util.ArrayList;
3//--or--
4import java.util.*
5
6ArrayList<DataType> name = new ArrayList<DataType>();
7//Defining an arraylist, substitute "DataType" with an Object
8//such as Integer, Double, String, etc
9//the < > is required
10//replace "name" with your name for the arraylist