layout | title | parent | nav_order |
---|---|---|---|
default |
Arraylist |
Collections |
2 |
Java ArrayList class uses a dynamic array for storing the elements. It inherits AbstractList class and implements List interface.
The important points about Java ArrayList class are:
- Java ArrayList class can contain duplicate elements.
- Java ArrayList class maintains insertion order.
- Java ArrayList class is non synchronized.
- Java ArrayList allows random access because array works at the index basis.
- In Java ArrayList class, manipulation is slow because a lot of shifting needs to occur if any element is removed from the array list.
import java.util.*;
class ArrayList1{
public static void main(String args[]){
ArrayList<String> list=new ArrayList<String>();//Creating arraylist
list.add("Ravi");//Adding object in arraylist
list.add("Vijay");
list.add("Ravi");
list.add("Ajay");
//Invoking arraylist object
System.out.println(list);
}
}
}
Output
[Ravi, Vijay, Ravi, Ajay]
import java.util.*;
class ArrayList2{
public static void main(String args[]){
ArrayList<String> list=new ArrayList<String>();//Creating arraylist
list.add("Ravi");//Adding object in arraylist
list.add("Vijay");
list.add("Ravi");
list.add("Ajay");
//Traversing list through Iterator
Iterator itr=list.iterator();
while(itr.hasNext()){
System.out.println(itr.next());
}
}
}
Output
Ravi
Vijay
Ravi
Ajay
import java.util.*;
class ArrayList3{
public static void main(String args[]){
ArrayList<String> al=new ArrayList<String>();
al.add("Ravi");
al.add("Vijay");
al.add("Ravi");
al.add("Ajay");
//Traversing list through for-each loop
for(String obj:al)
System.out.println(obj);
}
}
Output
Ravi
Vijay
Ravi
Ajay