import java.util.*;
import java.lang.*;
import java.io.*;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
 
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		String regex = "\\G\\[([^\\]\\[]*)]\\h+([^\\]\\[]+$)?";
		String string = "[2021-03-10 00:13:32.901] [DefaultDispatcher-worker-2 @coroutine#3] [DEBUG] [4231c006d9083a302fce59d5f0957226] [42c5ac3c0acfc68d] [GreeterImpl] Hello John";
 
		Pattern pattern = Pattern.compile(regex, Pattern.MULTILINE);
		Matcher matcher = pattern.matcher(string);
 
		while (matcher.find()) {
		    for (int i = 1; i <= matcher.groupCount(); i++) {
		    	if (matcher.group(i) != null) {
		        	System.out.println(matcher.group(i));
		    	}
		    }
		}
	}
}

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