question: public static void insertEmptyData ( ByteBuffer buffer , int len ) { byte [ ] buf = buffer . array ( ) ; int pos = buffer . position ( ) ; int limit = buffer . limit ( ) ; System . arraycopy ( buf , pos , buf , pos + len , limit - pos ) ; Arrays . fill ( buf , pos , pos + len , ( byte ) 0 ) ; buffer . limit ( limit + len ) ; }
target:  Inserts empty data of the given length at the current position of the given buffer (moving existing data forward the given length).  The limit of the buffer is adjusted by the given length.  The buffer is expecting to have the required capacity available.