ArrayList
In this chapter you will learn:
ArrayList Class
ArrayList is a resizable-array implementation of the List interface.
The ArrayList class extends AbstractList
and implements the List interface.
ArrayList supports dynamic arrays that can grow as needed.
An ArrayList is a variable-length array of object references,
whick can dynamically increase or decrease in size.
ArrayList is a generic class that has declaration of:
class ArrayList<E>
E specifies the type of objects that the list will hold.
ArrayList demo
A demonstration of an array-based list
import java.util.ArrayList;
import java.util.List;
//j av a 2s . com
public class Main {
public static void main(String[] args) {
List<String> ls = new ArrayList<String>();
String[] weekDays = { "A", "B", "C", "Wed", "Z", "Y", "X" };
for (String weekDay : weekDays){
ls.add(weekDay);
}
dump("ls:", ls);
ls.set(ls.indexOf("Wed"), "Wednesday");
dump("ls:", ls);
ls.remove(ls.lastIndexOf("X"));
dump("ls:", ls);
}
static void dump(String title, List<String> ls) {
System.out.print(title + " ");
for (String s : ls){
System.out.print(s + " ");
}
System.out.println();
}
}
The code above generates the following result.
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What you will learn in the next chapter:
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