Java Utililty Methods String Blur

String blur(String s)
replaces everything but the first and last letter of the input string s by '.'

if (!BLUR)
 return s;
if (s == null || s.length() <= 1)
 return s;
char c[] = s.toCharArray();
for (int i = 1; i < s.length() - 1; i++)
 c[i] = '.';
return new String(c);
...

String blurKeepingExtension(String s)
blurs a filename but keeps the extension intact.

if (s == null)
 return null;
int idx = s.lastIndexOf(".");
if (idx <= 0)
 return blur(s); 
int MAX_EXTENSION_LENGTH = 6;
if (s.length() - idx > MAX_EXTENSION_LENGTH)
 return blur(s); 
...