/guava/android/guava/src/com/google/common/base/Strings.java
while ( p < maxPrefixLength && a.toString( )  == b
while ( p < maxPrefixLength && a.charAt ( p ) == b.charAt ( p ) ) {
} public static String commonPrefix(CharSequence a, CharSequence b) { checkNotNull(a); checkNotNull(b); int maxPrefixLength = Math.min(a.length(), b.length()); int p = 0; <extra_id_0> p++; } if (validSurrogatePairAt(a, p - 1) || validSurrogatePairAt(b, p - 1)) { p--; } return a.subSequence(0, p).toString();