the browser keeps sending requests to check

(?<=^|s)p{L}

PS> $s = 'the browser keeps sending requests to check'
PS> -join [regex]::Matches($s, '(?<=^|s)p{L}')
tbksrtc

String str = "the browser keeps sending requests to check";
Matcher m = Pattern.compile("(\S)(\S+)").matcher(str);
while (m.find()) {
    System.out.print(m.group(1));
}

public String generateInitials (String original){
    String[] words= original.split(" ");
    return retrieveInitialsOfEachWord(words);
}

private String retrieveInitialsOfEachWord(String[] words){
    String initials = "";
    for(String word : words){
        initials += word.substring(0,1);
    }
    return initials;
}