Benefits of arraylist in java over arrays

Disadvantages of arrays:

• Check the disadvantages of arrays in below article.
• Advantages and disadvantages of arrays in java

Advantages / Benefits of arraylist in java:

• We have some disadvantages of arrays like arrays are fixed in length. and we need to mention size of the array while creation itself.
• So we have some advantages of arraylist when compared to arrays in java.
• Here  the major advantages of arraylist over arrays.

1.ArrayList is variable length

• One of the major benefit of arraylist is it is dynamic in size. we can increase as well as decrease size of the arraylist dynamically.
• Resizable.

Program #1: Java example program to explain the advantages of ArrayList: resizable

1. package collections;
2.  
3. import java.util.ArrayList;
4.  
5. public class ArrayListExample {
6.     /**
7.     * Advantages of arrayList over arrays in java
8.     * @author www.instanceofjava.com
9.     */
10.  public static void main(String[] args) {
11.         
12.         ArrayList<Integer> list = new ArrayList<Integer>();
13.          
14.         list.add(1);
15.  
16.         list.add(2);
17.  
18.         list.add(3);
19.  
20.         System.out.println(list.size());      
21.         list.add(4);
22.         list.add(5);
23.  
24.         System.out.println(list.size());     
25.         list.remove(1);
26.  
27.         System.out.println(list.size());    
28.     }
29. }

Output:

1. 3
2. 5
3. 4

• In the above program by using add and remove methods of ArrayList we can change the size of the ArrayList

2.Default initial capacity is 10.

• One of the major benefit of arraylist is by default it will assign default size as 10.
• Whenever we create object of ArrayList constructor of ArrayList assign default capacity as 10.

3.Insert and remove elements also at particular position of  ArrayList

• Another advantage of ArrayList is it can add and remove elements at particular position.

Program #2: Java example program to explain the advantages of ArrayList:Add and remove elements at particular position.

1. package collections;
2.  
3. import java.util.ArrayList;
4.  
5. public class ArrayListExample {
6.     /**
7.     * Advantages of arrayList over arrays in java
8.     * @author www.instanceofjava.com
9.     */
10.     public static void main(String[] args) {
11.         
12.         ArrayList<Integer> list = new ArrayList<Integer>();
13.          
14.         list.add(1);
15.  
16.         list.add(2);
17.  
18.         list.add(3);
19.  
20.         System.out.println(list);
21.  
22.         list.add(0,4);
23.         
24.         System.out.println(list);
25.         
26.         list.add(2,5);
27.  
28.       
29.         System.out.println(list);
30.         list.remove(3);
31.         
32.         System.out.println(list);
33.         System.out.println(list.size());    
34.     }
35. }

Output:

1. [1, 2, 3]
2. [4, 1, 2, 3]
3. [4, 1, 5, 2, 3]
4. [4, 1, 5, 3]
5. 4

4.Add any type of data into ArrayList.

• We can add different type of objects in to the ArrayList.
• In this scenario avoid mentioning generics while declaring ArrayList.

Program #3: Java example program to explain the advantages of ArrayList: Add any type of Object.

5.Traverse in both directions.

• We can traverse both direction using List Iterator.

Program #4: Java example program to explain the advantages of ArrayList: Traverse in both directions.

1. package collections;
2.  
3. import java.util.ArrayList;
4. import java.util.ListIterator;
5.  
6. public class ArrayListExample {
7.     /**
8.     * Advantages of arrayList over arrays in java
9.     * @author www.instanceofjava.com
10.     */
11.     public static void main(String[] args) {
12.         
13.         ArrayList<String> list = new ArrayList<String>();
14.          
15.         list.add("ArrayList Advantages");
16.  
17.         list.add("ArrayList benefits");
18.         
19.         list.add("ArrayList in java");
20.  
21.         ListIterator iterator = list.listIterator();
22.         
23.         System.out.println("**ArrayList Elements in forward direction**");
24.          
25.         while (iterator.hasNext())
26.         {
27.             System.out.println(iterator.next());
28.         }
29.          
30.         System.out.println("**ArrayList Elements in backward direction**");
31.          
32.         while (iterator.hasPrevious())
33.         {
34.             System.out.println(iterator.previous());
35.         } 
36.     }
37. }

 Output:

1. **ArrayList Elements in forward direction**
2. ArrayList Advantages
3. ArrayList benefits
4. ArrayList in java
5. **ArrayList Elements in backward direction**
6. ArrayList in java
7. ArrayList benefits
8. ArrayList Advantages

6.ArrayList allows Multiple null values

• We can add multiple null elements to ArrayList

Program #5: Java example program to explain the benefits of ArrayList: Add null elements

1. package collections;
2.  
3. import java.util.ArrayList;
4.  
5. public class ArrayListExample {
6.     /**
7.     * Advantages of arrayList over arrays in java
8.     * @author www.instanceofjava.com
9.     */
10.     public static void main(String[] args) {
11.         
12.         ArrayList<String> arraylist = new ArrayList<String>();
13.          
14.         arraylist.add(null);
15.  
16.         arraylist.add(null);
17.         
18.         arraylist.add(null);
19.  
20.         System.out.println(arraylist);
21.     }
22. }

Output:

1. [null, null, null]

7.ArrayList allows to add duplicate elements

• We can add duplicate elements into arrayList

Program #6: Java example program to explain the advantages of ArrayList: Add any type of Object.

1. package collections;
2.  
3. import java.util.ArrayList;
4.  
5. public class ArrayListExample {
6.     /**
7.     * Advantages of arrayList over arrays in java
8.     * @author www.instanceofjava.com
9.     */
10.     public static void main(String[] args) {
11.         
12.         ArrayList<String> arraylist = new ArrayList<String>();
13.          
14.        arraylist.add("ArrayList");
15.  
16.         arraylist.add("ArrayList");
17.         
18.         arraylist.add("ArrayList");
19.  
20.         System.out.println(arraylist);
21.     }
22. }

Output:

1. [ArrayList, ArrayList, ArrayList]

8.ArrayList has many methods to manipulate stored objects.

• ArrayList has many methods to manipulate stored objects.
• addAll(), isEmpty(). lastIndexOf() etc.