Fastest way to strip all non-printable characters from a Java String

What is the fastest way to strip all non-printable characters from a String in Java?

So far I've tried and measured on 138-byte, 131-character String:

• String's replaceAll() - slowest method
  • 517009 results / sec
• Precompile a Pattern, then use Matcher's replaceAll()
  • 637836 results / sec
• Use StringBuffer, get codepoints using codepointAt() one-by-one and append to StringBuffer
  • 711946 results / sec
• Use StringBuffer, get chars using charAt() one-by-one and append to StringBuffer
  • 1052964 results / sec
• Preallocate a char[] buffer, get chars using charAt() one-by-one and fill this buffer, then convert back to String
  • 2022653 results / sec
• Preallocate 2 char[] buffers - old and new, get all chars for existing String at once using getChars(), iterate over old buffer one-by-one and fill new buffer, then convert new buffer to String - my own fastest version
  • 2502502 results / sec
• Same stuff with 2 buffers - only using byte[], getBytes() and specifying encoding as "utf-8"
  • 857485 results / sec
• Same stuff with 2 byte[] buffers, but specifying encoding as a constant Charset.forName("utf-8")
  • 791076 results / sec
• Same stuff with 2 byte[] buffers, but specifying encoding as 1-byte local encoding (barely a sane thing to do)
  • 370164 results / sec

My best try was the following:

    char[] oldChars = new char[s.length()];
    s.getChars(0, s.length(), oldChars, 0);
    char[] newChars = new char[s.length()];
    int newLen = 0;
    for (int j = 0; j < s.length(); j+