I-java.lang.nullpointerexception yimposiso yeJava eyenzekayo xa isicelo seJava sizama ukusebenzisa i-null endaweni yento.
I-RuntimeException yandiswe yi-NullPointerException, eludidi lukawonke-wonke.
I-NullPointerException iphakanyiswe kwiimeko ezahlukeneyo, njengaxa ubiza indlela yomzekelo wento engekhoyo. Le mpazamo iyakwenzeka kwakhona ukuba into ililize kwaye uzama ukufikelela okanye ukuhlela umhlaba waloo nto ililize.
Ukuba uzama ukufumana ubude be-null array, ngaphandle kuya kuphakanyiswa ngokunjalo.
Kweli nqaku, siza kujonga indlela yokuphatha i-Null Pointer Exception kwiJava.
Xa i-java.lang.nullpointerexception isenzeka?
Xa uguqulo lwe-java olungalathi kuyo nayiphi na into lufikelelwe kuso nasiphi na isenzo, kuvela i-java.lang.nullpointerexception.
Ixesha lokusebenza ngaphandle kwe-java.lang.nullpointerexceptionition kwi-runtime yi-java.lang.nullpointinterexception. Xa uchaza ukuguquguquka kodwa ungayibeki kwinto de ube uzama ukuyisebenzisa, uya kufumana i-nullpointerexception ye-java.
Ubhekisa kwinto engekhoyo. KwiJava, i-null ibonisa ixabiso elithile. Idla ngokusetyenziswa ukubonisa ukuba ireferensi eguquguqukayo ayinikwanga xabiso okanye ayinikwanga xabiso.
Ukunqanda i-NullPointerException, qiniseka ukuba zonke izinto ziqaliswe ngokufanelekileyo ngaphambi kokusebenzisa ukuguquguquka.
Ezi zilandelayo zezinye zezona meko zixhaphakileyo ze-NullPointerException:
- Ukufumana iimpawu zento engenanto
- Ukusebenzisa into engekhoyo ukubiza iindlela
- Kwinto engento, kusetyenziswa ungqamaniso
- Ukuphosa i-null ukusuka kwindlela yokuphosa ngaphandle
- Iimpikiswano ezingephi zigqithiselwa kwindlela.
- Ukufikelela kwisalathiso sento engenanto (njengakuluhlu)
- Kwinkqubo yesitofu sokuxhomekeka njengeNtwasahlobo, olu seto aluchanekanga.
Umzekelo we-java.lang.nullpointerexception
I-NullPointerException iyakuphoswa ukuba uguqulo lweJava lwenziwe olungabhekiseli entweni kwaye lusetyenziselwa ukuphumeza umsebenzi othile.
Lo mzekelo ulandelayo uzama ukumisela ubude bomtya omiselwe ukuba ube lilize.
Ukulungisa i-java.lang.nullpointerexception
Lungisa 1
Fumana i-java eguquguqukayo ephosa i-java.lang ngaphandle. Ukuba isoftware iphosa i-NullPointerException, jonga kabini ukuba uguqulo lwabelwe ixabiso okanye into.
I-java.lang.nullpointerexception iyakuchithwa ukuba ixabiso labelwe i-java variable.
Lungisa 2
Sebenzisa umsebenzisi weternary ukukhankanya ixabiso elimiselweyo phambi kokusebenzisa i-java variable ukwenza isenzo ukuba i-java.lang.nullpointerexception iphoswe kuguquguquko.
Ixabiso loguqulo luya kusetyenziswa ukuba unalo. Kungenjalo, ukunqanda i-java.lang.nullpointerexception, ixabiso elingagqibekanga liya kusetyenziswa.
Lungisa 3
Ukuba awuqinisekanga ukuba yeyiphi na inguqu edala i-java.lang.nullpointerexception okanye ukuba kukho ithuba lokujula i-java.lang.nullpointerexception, okanye ukuba kukho umngcipheko wokujula i-java.lang.nullpointerexception kwiindawo ezininzi; kuthatha ixesha ukongeza i-null check kwikhowudi.
Ukusingatha umcimbi yongeza ibhloko yokubambisa kuyo.
Lungisa 4
Ukuba i-java eguquguqukayo kwisicelo iphosa i-java.lang.nullpointerexception, yenza ukukhangela okungafunekiyo phambi kokuyisebenzisa.
Thatha enye indlela ukuba uguqulo alunamsebenzi. I-java.nullpointerexception iya kususwa.
isiphelo
Kweli nqaku, sijonge iJava NullPointerException.
Le yimeko eyahlukileyo eyingozi edla ngokuvela xa singayilindelanga. Esona sizathu sixhaphakileyo seNqaku leSikhombisi seNull yinto engekhoyo okanye ireferensi engeyiyo.
Sele sizibonile ezona zisombululo zisebenzayo.
Shiya iMpendulo