Java String length() Method: How to Get a String’s Size (Example)

Understanding Java’s String.length() Method

The length() method is a core part of Java’s String API. It returns the number of 16‑bit Unicode code units in a string, which is effectively the string’s size in characters for most text. This method is read‑only; it does not modify the string itself.

Syntax

public int length()

Parameters: None

Return Value: The number of characters (Unicode code units) in the string.

Practical Example

Below is a simple Java program that demonstrates how to retrieve the length of two different strings. The output shows the numeric result for each string.

public class SampleString {
    public static void main(String[] args) {
        // Define two String objects
        String s1 = "Hello Java String Method";
        String s2 = "RockStar";

        // Use length() to get the size of each string
        int length1 = s1.length();
        System.out.println("Length of s1: " + length1);

        System.out.println("Length of s2: " + s2.length());
    }
}

Output:

Length of s1: 24
Length of s2: 8

Why It Matters

Knowing a string’s length is fundamental for tasks such as input validation, text parsing, and buffer allocation. Because length() operates in constant time, it’s efficient even for very long strings.

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