question: @ SuppressWarnings ( "unchecked" ) protected final void ensureCapacity ( long targetSize ) { long capacity = capacity ( ) ; if ( targetSize > capacity ) { inflateSpine ( ) ; for ( int i = spineIndex + 1 ; targetSize > capacity ; i ++ ) { if ( i >= spine . length ) { int newSpineSize = spine . length * 2 ; spine = Arrays . copyOf ( spine , newSpineSize ) ; priorElementCount = Arrays . copyOf ( priorElementCount , newSpineSize ) ; } int nextChunkSize = chunkSize ( i ) ; spine [ i ] = ( E [ ] ) new Object [ nextChunkSize ] ; priorElementCount [ i ] = priorElementCount [ i - 1 ] + spine [ i - 1 ] . length ; capacity += nextChunkSize ; } } }
target:  Ensure that the buffer has at least capacity to hold the target size