A DESCRIPTION OF THE REQUEST :
String and AbstractStringBuilder both have a

 public void getChars(int srcBegin, int srcEnd, char dst[], int dstBegin)

method. Unfortunately this method is not in CharSequence.

JUSTIFICATION :
java.lang.CharSequence has a method

 CharSequence subSequence(int start, int end)

to get parts of the sequence. So there is no reason why there shouldn't be also a

 public void getChars(int srcBegin, int srcEnd, char dst[], int dstBegin)

to read character data efficiently into an existind buffer. This would allow for efficient generalizations.

Example:
StringReader then could take CharSequence as construction parameter wo wrap arbitrary CharSequences in Readers. It could then copy character data while avoiding unneccessary in-memory copies of these data.


CUSTOMER SUBMITTED WORKAROUND :
Make case differentiations between String, StringBuffer, StringBuilder,...