question: public void writeBytes ( int position , int num , byte [ ] buf ) { if ( buf . length < num ) { throw new PageException ( "num bytes to write is longer than buffer" ) ; } if ( position < 0 || num < 0 ) { throw new PageException ( "position or num can't be negative" ) ; } if ( Page . pageSize < num + position ) { throw new PageException ( "writeBytes would go out of bounds" ) ; } pageData . position ( position ) ; pageData . put ( buf , 0 , num ) ; }
target:  Write num bytes from buf at offset position.