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In this guide, you will learn about the String isEmpty() method in Java programming and how to use it with an example.
1. String isEmpty() Method Overview
Definition:
The isEmpty() method in Java's String class is utilized to check if a given string has a length of zero, essentially determining whether the string is empty or not.
Syntax:
str.isEmpty()
Parameters:
- The method takes no parameters.
Key Points:
- Returns true if the string has a length of 0, otherwise false.
- It's a more readable alternative to checking the string length using str.length() == 0.
- Useful in scenarios like form validation, parsing input, etc., to ensure data presence.
2. String isEmpty() Method Example
public class IsEmptyExample {
public static void main(String[] args) {
String emptyString = "";
String nonEmptyString = "Java";
String whitespaceString = " ";
// Checking an empty string
boolean isEmpty1 = emptyString.isEmpty();
System.out.println("Is the emptyString empty? " + isEmpty1);
// Checking a non-empty string
boolean isEmpty2 = nonEmptyString.isEmpty();
System.out.println("Is the nonEmptyString empty? " + isEmpty2);
// Checking a whitespace string
boolean isEmpty3 = whitespaceString.isEmpty();
System.out.println("Is the whitespaceString empty? " + isEmpty3);
}
}
Output:
Is the emptyString empty? true Is the nonEmptyString empty? false Is the whitespaceString empty? false
Explanation:
In the example:
1. We first check an empty string using the isEmpty() method. As expected, the method returns true for the empty string.
2. Next, we check a non-empty string "Java". Since the string contains characters, the method returns false.
3. Lastly, we evaluate a string containing just a whitespace. It's essential to note that the isEmpty() method considers a string with whitespace as non-empty. Therefore, it returns false.
Related Java String Class method examples
- Java String charAt() example
- Java String concat() example
- Java String contains() example
- Java String endsWith() example
- Java String equals() example
- Java String equalsIgnoreCase() example
- Java String getBytes() example
- Java String indexOf() example
- Java String isEmpty() example
- Java String lastIndexOf() example
- Java String length() example
- Java String replace() example
- Java String split() example
- Java String startsWith() example
- Java String substring() example
- Java String toLowerCase() example
- Java String toUpperCase() example
- Java String trim() example
- Java String valueOf() example
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