Regular expression to match exact string with with non-numeric characters and variable number

Question

I have been struggling with this and would appreciate any help.

I have a line of code that always looks like this:

Thread.sleep(1000)

Thread.sleep() is always a fixed sequence of characters, but the integer number inside is variable. How would I write a regular expression to catch this?

Answer 1

You can use the regex, Thread\s*\.\s*sleep\s*\(\s*\d+\s*\).

Explanation of the regex:

• Thread: Literal, Thread
• \s*\.\s*: . preceded by and followed by 0+ whitespace characters
• sleep\s*: Literal, sleep followed by 0+ whitespace characters
• \(\s*: The character, ( followed by 0+ whitespace characters
• \d+\s*: One or more digits followed by 0+ whitespace characters
• \): The character, )

Demo:

public class Main {
    public static void main(String[] args) {
        String x = "Some Thread.sleep(1000) text";
        x = x.replaceAll("Thread\\s*\\.\\s*sleep\\s*\\(\\s*\\d+\\s*\\)", "");
        System.out.println(x);
    }
}

Output:

Some  text