Java New String Class Methods from Java 8 to Java 17

The Java programming language has been a staple in the world of software development for decades, known for its robustness and versatility. With each new release, the Java platform introduces enhancements and new features that make developers' lives easier and code more efficient.

Among these additions, the evolution of string manipulation methods has been particularly notable. In this section, we will explore the journey of Java String class methods from Java 8 to Java 17, highlighting the improvements and benefits they bring to developers.

Java 8: String.join() Method

Released in March 2014, Java 8 brought about a significant update to string manipulation with the introduction of the String.join(CharSequence delimiter, CharSequence... elements) method. Prior to this, developers had to rely on manual iteration and concatenation to join strings with a specific delimiter. The new method simplified this process by providing a cleaner and more readable way to concatenate strings.

List<String> words = Arrays.asList("Hello", "world", "Java");
String result = String.join(" ", words);
System.out.println(result); // Output: "Hello world Java"

Java 11: String.isBlank() and String.strip() Method

In September 2018, Java 11 was released with two important string-related methods: isBlank() and strip(). The isBlank() method checks whether a string is empty or contains only whitespace characters. This is a more intuitive alternative to the traditional trim().isEmpty() combination.

String emptyStr = "";
String whitespaceStr = "     ";
System.out.println(emptyStr.isBlank()); // Output: true
System.out.println(whitespaceStr.isBlank()); // Output: true

The strip() method, on the other hand, removes leading and trailing whitespace characters from a string. This is an improvement over the trim() method, which only removed ASCII control characters from the ends of the string.

String paddedStr = "   Java 11   ";
System.out.println(paddedStr.strip()); // Output: "Java 11"

Java 12: String.indent(int n) Method

Java 12, released in March 2019, introduced the String.indent(int n) method, which indents each line of a string by a specified number of spaces. This is useful when formatting strings that are meant to be displayed with a certain level of indentation.

String text = "Line 1\nLine 2\nLine 3";
System.out.println(text.indent(4));

Java 15: String.repeat(int count) Method

The repeat(int count) method, added in September 2020 with Java 15, simplifies the process of repeating a string a certain number of times. Prior to this addition, developers often resorted to using loops or StringBuilder to achieve the same effect.

String repeated = "Java ".repeat(3);
System.out.println(repeated); // Output: "Java Java Java "

Java 17: Enhanced String::formatted Method

Java 17, released in September 2021, enhanced the String::formatted method introduced in Java 15. The formatted method provides a more readable and concise way to create formatted strings by replacing placeholders with values. In Java 17, it gained the ability to use named placeholders for better readability.

String name = "Alice";
int age = 30;
String formattedString = "Name: %s, Age: %d".formatted(name, age);
System.out.println(formattedString); // Output: "Name: Alice, Age: 30"

Let's implement the above discussed method in a Java program.

Filename: StringMethodsDemo.java

import java.util.Arrays;
import java.util.List;
public class StringMethodsDemo {
    public static void main(String[] args) {
        // Java 8 - String.join()
        List<String> words = Arrays.asList("Hello", "world", "Java");
        String result = String.join(" ", words);
        System.out.println("Java 8 - String.join(): " + result); // Output: "Hello world Java"
        // Java 11 - String.isBlank() and String.strip()
        String emptyStr = "";
        String whitespaceStr = "     ";
        System.out.println("Java 11 - String.isBlank(): " + emptyStr.isBlank()); // Output: true
        System.out.println("Java 11 - String.isBlank(): " + whitespaceStr.isBlank()); // Output: true
        String paddedStr = "   Java 11   ";
        System.out.println("Java 11 - String.strip(): " + paddedStr.strip()); // Output: "Java 11"
        // Java 12 - String.indent()
        String text = "Line 1\nLine 2\nLine 3";
        System.out.println("Java 12 - String.indent():\n" + text.indent(4));
        // Java 15 - String.repeat()
        String repeated = "Java ".repeat(3);
        System.out.println("Java 15 - String.repeat(): " + repeated); // Output: "Java Java Java "
        // Java 17 - Enhanced String::formatted
        String name = "Alice";
        int age = 30;
        String formattedString = "Name: %s, Age: %d".formatted(name, age);
        System.out.println("Java 17 - Enhanced String::formatted: " + formattedString); // Output: "Name: Alice, Age: 30"
    }
}

Output:

Java 8 - String.join(): Hello world Java
Java 11 - String.isBlank(): true
Java 11 - String.isBlank(): true
Java 11 - String.strip(): Java 11
Java 12 - String.indent():
    Line 1
    Line 2
    Line 3
Java 15 - String.repeat(): Java Java Java 
Java 17 - Enhanced String::formatted: Name: Alice, Age: 30

Conclusion

The evolution of string manipulation methods from Java 8 to Java 17 demonstrates Java's commitment to improving developer productivity and code readability. With each release, new methods have been introduced to simplify common string-related tasks, making the code cleaner and more concise.

The join() method in Java 8 to the enhancements in Java 17, these additions have undoubtedly made string manipulation in Java a more enjoyable experience for developers. As the Java platform continues to evolve, we can look forward to even more innovations that enhance the language's capabilities.

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