length vs length() in Java

array.length : length is a final variable applicable for arrays. With the help of length variable, we can obtain the size of the array.
string.length() : length() method is a final variable which is applicable for string objects. length() method returns the number of characters presents in the string.

length vs length()

1. The length variable is applicable to array but not for string objects whereas the length() method is applicable for string objects but not for arrays.
2. Examples:

   // length can be used for int[], double[], String[] 
   // to know the length of the arrays.
   
   // length() can be used for String, StringBuilder, etc 
   // String class related Objects to know the length of the String

3. To directly accesses a field member of array we can use .length; whereas .length() invokes a method to access a field member.

Example:

Output:

The size of the array is 4
The size of the String is 13

Practice Questions based on the concept of length vs length()

Lets have a look on the output of the following programs?

1. What will be the output of following program?
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   public class Test { public static void main(String[] args)     {         // Here str is the array name of String type.         String[] str = { "GEEKS", "FOR", "GEEKS" };         System.out.println(str.length);     } }

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   Output:

   3
   

   Explanation: Here the str is an array of type string and that’s why str.length is used to find its length.

2. What will be the output of following program?
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   public class Test { public static void main(String[] args)     {         // Here str[0] pointing to a string i.e. GEEKS         String[] str = { "GEEKS", "FOR", "GEEKS" };         System.out.println(str[0].length);     } }

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   Output:

   error: cannot find symbol
   symbol: method length()
   location: variable str of type String[]
   

   Explanation: Here the str is an array of type string and that’s why str.length() CANNOT be used to find its length.

3. What will be the output of following program?
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   public class Test { public static void main(String[] args)     {         // Here str[0] pointing to String i.e. GEEKS         String[] str = { "GEEKS", "FOR", "GEEKS" };         System.out.println(str[0].length());     } }

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   Output:

   5

   Explanation: Here str[0] pointing to String i.e. GEEKS and thus can be accessed using .length()

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