question: public void add ( int i , byte [ ] buffer , int offset , int length ) { if ( _length + length > _capacity ) ensureCapacity ( _length + length ) ; System . arraycopy ( _buffer , i , _buffer , i + length , _length - i ) ; System . arraycopy ( buffer , offset , _buffer , i , length ) ; _length += length ; }
target:  Inserts a byte array