How to use new String methods in Java 11?

Introduction

Java 11 introduced several new and improved String methods that offer enhanced functionality and flexibility for Java developers. This tutorial will guide you through the key new String methods, their practical applications, and how to effectively utilize them in your Java projects.

Skills Graph

Overview of New String Methods in Java 11

Java 11, released in 2018, introduced several new and powerful String methods that enhance the language's string handling capabilities. These new methods provide developers with more efficient and versatile tools for working with strings, making their code more concise, readable, and performant.

In this section, we'll explore the key new String methods introduced in Java 11, their use cases, and how to effectively leverage them in your Java applications.

New String Methods in Java 11

The following are the new String methods introduced in Java 11:

1. isBlank(): This method returns true if the string is empty or contains only whitespace characters, and false otherwise.
2. lines(): This method returns a stream of lines extracted from the string, separated by line terminators.
3. strip(), stripLeading(), and stripTrailing(): These methods remove leading and/or trailing whitespace from the string.
4. repeat(int count): This method returns a string consisting of the original string repeated count times.
5. describeConstable() and resolveConstantDesc(): These methods provide support for constant descriptions, which can be used to improve the performance of string operations.

// Example usage of new String methods in Java 11
String input = "   Hello, World!   ";

System.out.println(input.isBlank());       // false
System.out.println(input.strip());         // "Hello, World!"
System.out.println(input.stripLeading());  // "Hello, World!   "
System.out.println(input.stripTrailing()); // "   Hello, World!"
System.out.println(input.repeat(3));       // "   Hello, World!   Hello, World!   Hello, World!   "

In the next section, we'll dive deeper into the practical use cases and benefits of these new String methods.

Exploring the Powerful String Methods

isBlank() Method

The isBlank() method is a useful tool for checking if a string is empty or contains only whitespace characters. This method can be particularly helpful in input validation, where you need to ensure that a user has provided a meaningful value.

String input1 = "   ";
String input2 = "Hello, World!";

System.out.println(input1.isBlank()); // true
System.out.println(input2.isBlank()); // false

lines() Method

The lines() method allows you to easily split a string into a stream of individual lines. This can be useful for processing text data, such as log files or configuration files, where you need to operate on each line separately.

String multilineString = "Line 1\nLine 2\nLine 3";
multilineString.lines().forEach(System.out::println);

strip(), stripLeading(), and stripTrailing() Methods

These methods provide a convenient way to remove leading and/or trailing whitespace from a string. This can be particularly useful when working with user input or parsing data from external sources.

String input = "   Hello, World!   ";
System.out.println(input.strip());         // "Hello, World!"
System.out.println(input.stripLeading());  // "Hello, World!   "
System.out.println(input.stripTrailing()); // "   Hello, World!"

repeat() Method

The repeat() method allows you to create a new string by repeating the original string a specified number of times. This can be useful for generating repeated patterns or filling in templates.

String greeting = "Hello, ";
String repeatedGreeting = greeting.repeat(3);
System.out.println(repeatedGreeting); // "Hello, Hello, Hello, "

In the next section, we'll explore some practical use cases for these new String methods.

Practical Use Cases for the New String Features

Input Validation and Cleaning

The isBlank() and strip() methods can be used to validate and clean user input, ensuring that the data is meaningful and free of unnecessary whitespace.

String userInput = "   hello   ";
if (!userInput.isBlank()) {
    String cleanedInput = userInput.strip();
    System.out.println("Cleaned input: " + cleanedInput);
} else {
    System.out.println("Input is blank!");
}

Text Processing and Formatting

The lines() method can be used to process multi-line text, such as log files or configuration data, by allowing you to work with each line individually.

String logData = "ERROR: Something went wrong\nWARNING: This is a warning\nINFO: Everything is fine";
logData.lines()
      .filter(line -> line.startsWith("ERROR"))
      .forEach(System.out::println);

The repeat() method can be used to generate repeated patterns or fill in templates, which can be useful for tasks like creating padded strings or generating repetitive content.

String separator = "-".repeat(20);
System.out.println(separator); // "--------------------"

Constant Descriptions

The describeConstable() and resolveConstantDesc() methods provide support for constant descriptions, which can be used to improve the performance of string operations. This feature is particularly useful for libraries and frameworks that work with a large number of constant values.

public enum Color {
    RED, GREEN, BLUE;

    public String getDescription() {
        return this.describeConstable().orElse(this.name());
    }
}

Color color = Color.RED;
System.out.println(color.getDescription()); // "RED"

By leveraging these new String methods, you can write more concise, efficient, and maintainable Java code that handles string-related tasks with ease.

Summary

The new String methods in Java 11 provide Java developers with a powerful set of tools to manipulate and work with strings more efficiently. By understanding and applying these methods, you can streamline your Java programming, improve code readability, and enhance the overall quality of your applications. This tutorial has explored the capabilities of these new String features and demonstrated their practical use cases, equipping you with the knowledge to leverage them in your own Java projects.