/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
import java.util.regex.*;
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		String s = "[what, ask, about, group, differences, , , or, differences, in, conditions, |? |]";
		StringBuffer result = new StringBuffer();
		Matcher m = Pattern.compile("((?:\\s*,){3})|,").matcher(s);
		while (m.find()) {
    		if (m.group(1) != null) {
    		    m.appendReplacement(result, ",");
    		}
    		else {
    			m.appendReplacement(result, "");
    		}
 
		}
		m.appendTail(result);
		System.out.println(result.toString());
 
	}
}

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