array.length: length is the last variable that applies to the array. With the help of variable length we can determine the size of the array.

string.length(): The long() method is the last variable that applies to a String object. The long() method returns the number of characters present in the string.

length vs length():

1. The variable length applies to arrays but not to String objects, while the length() method applies to String objects but not to arrays. 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. We can use .length for direct access to array field elements; .Length() calls the method to access the field element.

Example:  

// Java program to illustrate the
// concept of length
// and length()
public class Test {
	public static void main(String[] args)
	{
		// Here array is the array name of int type
		int[] array = new int[4];
		System.out.println("The size of the array is "
						+ array.length);

		// Here str is a string object
		String str = "GeeksforGeeks";
		System.out.println("The size of the String is "
						+ str.length());
	}
}

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()

Let’s have a look at the output of the following programs:

• What will be the output of the following program?

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);
	}
}

Output

3

Explanation: Here str is an array of type string and therefore str.length is used to specify the length.

• What will be the output of the following program? 

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.length());
	}
}

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.  

• What will be the output of the following program?

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());
	}
}

Output

5

Explanation:

 Here str[0] points to a string, i.e. GEEKS and hence can be called via .length()