Metadata

ID: java-best-practices/inefficient-empty-string-test

Language: Java

Severity: Notice

Category: Best Practices

Description

This rule encourages developers to avoid using inefficient methods to check for empty strings, such as str.equals(""). Instead, it recommends using the more efficient and readable str.isEmpty() method. The isEmpty() method is specifically designed to check if a string has zero length, making it a clearer and more performant choice.

Using str.equals("") can be less efficient because it involves a method call that compares the content of the string, which may incur unnecessary overhead. Additionally, it can be less readable and more error-prone, especially if str might be null and proper null checks are not performed.

To comply with this rule, always use str.isEmpty() when checking if a string is empty. This improves code clarity and performance. For example, instead of writing if (str.equals("")), write if (str.isEmpty()). This small change leads to cleaner and more efficient code.

Non-Compliant Code Examples

public class MyClass {
    public void method() {
        if (str.equals("")) {
            System.out.println("foo");
        }
    }
}

Compliant Code Examples

public class MyClass {
    public void method() {
        if (str.isEmpty()) {
            System.out.println("foo");
        }
    }
}