how to get a list length in java

1        Collection<Object> list = new ArrayList<>();
2        list.size();
3        
4        // All collections use size()
5        // array use array. length 
6

1import java.util.ArrayList;
2import java.util.List;
3public class Demo {
4   public static void main(String[] args) {
5      List aList = new ArrayList();
6      aList.add("Apple");
7      aList.add("Mango");
8      aList.add("Guava");
9      aList.add("Orange");
10      aList.add("Peach");
11      System.out.println("The size of the ArrayList is: " + aList.size());
12   }
13}

1a.size() where a is list