▁in ▁callback s . ▁The ▁callback s ▁and ▁the ▁sequence ▁in ▁which ▁they ▁are ▁called ▁are ▁defined ▁by ▁the ▁url . ▁The ▁programmer ▁can ▁define ▁before ▁and ▁after ▁callback s ▁for ▁all ▁actions , ▁url - variables ▁and ▁url - re ferences . ▁They ▁are ▁called ▁in ▁the ▁order ▁in ▁which ▁the ▁corresponding ▁url - variable ▁and ▁url - reference ▁are ▁defined ▁in ▁the ▁url . ▁ ▁The ▁web - page ▁rendering ▁is ▁done ▁with ▁standard ▁technology , ▁like ▁J SP , ▁Apache ▁Vel ocity ▁or ▁Free Marker . ▁z templates ▁cho oses ▁the ▁correct ▁rendering ▁technology ▁and ▁template ▁from ▁the ▁annotation ▁the ▁programmer ▁attach es ▁to ▁a ▁plain ▁old ▁java ▁object . ▁ ▁z templates ▁integr ates ▁with ▁maven ▁and ▁is ▁available ▁from ▁the ▁maven ▁central ▁repository . ▁ ▁z templates ▁also ▁integr ates ▁with ▁Spring ▁and ▁ex poses ▁its ▁services ▁as ▁spring ▁be ans . ▁ ▁Since ▁ 0 . 9 . 9 ▁z templates ▁comes ▁with ▁support ▁for ▁AJAX ▁frameworks ▁and ▁a ▁sample ▁Y ahoo ▁UI ▁( Y UI ) ▁and ▁Google ▁Search ▁integration . ▁The ▁AJAX ▁libraries ▁are ▁included ▁by ▁dro pping ▁a ▁jar ▁file ▁into ▁the ▁applications ▁W EB - INF / lib ▁directory . ▁When ▁using ▁pre defined ▁components , ▁the ▁programmer ▁does ▁not ▁need ▁to ▁know ▁which ▁JavaScript ▁libraries ▁are ▁needed , ▁the ▁framework ▁cho oses ▁the ▁needed ▁ones ▁from ▁annotations ▁on ▁the ▁po jos ▁used . ▁ ▁Since ▁version ▁ 2 . 3 . 0 ▁z templates ▁contains ▁a ▁javascript ▁component ▁model ▁to ▁support ▁AJAX