Question

I’m trying to debug something and I’m wondering if the following code could ever return true

public boolean impossible(byte[] myBytes) {
  if (myBytes.length == 0)
    return false;
  String string = new String(myBytes, "UTF-8");
  return string.length() == 0;
}

Is there some value I can pass in that will return true? I’ve fiddled with passing in just the first byte of a 2 byte sequence, but it still produces a single character string.

To clarify, this happened on a PowerPC chip on Java 1.4 code compiled through GCJ to a native binary executable. This basically means that most bets are off. I’m mostly wondering if Java’s ‘normal’ behaviour, or Java’s spec made any promises.

Answer 1

According to the javadoc for java.util.String, the behavior of new String(byte[], “UTF-8”) is not specified when the bytearray contains invalid or unexpected data. If you want more predictability in your resultant string use http://java.sun.com/j2se/1.5.0/docs/api/java/nio/charset/CharsetDecoder.html.