How can Java remove leading whitespace?

Question

I have been trying to figure out why this Java code won't delete any leading whitespace to my actual string, I have been trying to use stripLeading() method and the trim(); method, and various other methods with the same functionality but still haven't gotten a favorable outcome. Code:

public static String message(String logLine) {
         logLine = (String) logLine.subSequence(logLine.indexOf(" ") + 1, logLine.length());
         return logLine;
         }
public static void main(String[] args) {
        
        System.out.println(message("[WARNING]:   \tTimezone not set  \r\n"));
    }

What results is what I wanted, just the words "Timezone not set" however I want this program to completely ignore leading whitespace, which for some reason it can't. Thank you for any help.

Answer 1

Possible solutions

• Use String::replaceFirst to keep only the part after a prefix ([WARNING]:) followed by whitespaces and the main part:

  public static String message(String logLine) {
      return logLine.replaceFirst("^\\S*\\s+(\\S+(\\s+\\S+)*)\\s+$", "$1");
  }
  

• As the prefix ends with ':', a solution offered in the comment using String::substring + String::trim works too:

  public static String message(String logLine) {
      return logLine.substring(logLine.indexOf(":") + 1).trim();
  }