/guava/guava/src/com/google/common/base/CaseFormat.java
out = new StringBuilder( s.length( ) + 4 * sourceFormat.wordSeparator.length( ) ) ;
out = new StringBuilder ( s.length ( ) + 4 * format.wordSeparator.length ( ) ) ;
String convert(CaseFormat format, String s) { StringBuilder out = null; int i = 0; int j = -1; while ((j = wordBoundary.indexIn(s, ++j)) != -1) { if (i == 0) { <extra_id_0> out.append(format.normalizeFirstWord(s.substring(i, j))); } else { requireNonNull(out).append(format.normalizeWord(s.substring(i, j))); } out.append(format.wordSeparator); i = j + wordSeparator.length();