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Top 68 Kotlin Interview Questions
Entry Junior Mid Senior Expert
Theoretical Questions
Q1i5N9:
znvabifHow to correctly concatenate a xkorsStringlbdc in Kotlin?jcnyl
Stringlbdc in Kotlin?jcnyl Junior
Q2yeC:
zykhpWhat is a xntnfldwacdata classoxocbdldrix in Kotlin?chpo
Junior
Q3Pct:
iatxwyyHow to eatgbbbszqinitialize an arrayxcnwezae in Kotlin with values?gjz
Junior
Q4rks84:
wqvlhzWhat is the jexfwemvidiomaticxmghpvdggygfoj way to hdrunrglznremove duplicate stringsizhmxbdsjk from array?godxq
Junior
Q56W38G:
mvlaWhere should I use bgqfvarczq and where gpvvallgkt?zmgyv
varczq and where gpvvallgkt?zmgyv Junior
Q6DS1eN:
tooWhat is the difference between nmzwkvarwldcj and lywscvaluslk in Kotlin?dpsahc
varwldcj and lywscvaluslk in Kotlin?dpsahc Junior
Q7SPx:
tbwkpWhat is basic difference between vdbeplfoldhltgzyn and olplreduceuftyu in Kotlin? When to use which?pvv
foldhltgzyn and olplreduceuftyu in Kotlin? When to use which?pvv Junior
Q8QoU:
qdiatWhat is a dimdqqdwdyprimary constructorrgxeleziqedk in Kotlin?hhy
Junior
Q9HBfWV:
zsyMay you use rrwwvsIntArraysdfleeg and an lnsArray<Int>dhys is in Kotlin interchangeably?ekg
IntArraysdfleeg and an lnsArray<Int>dhys is in Kotlin interchangeably?ekgQ10dED28:
tzqWhat are the advantages of Kotlin over Java?zcstk
Q11Eqv:
hpjuExplain advantages of qnfowhengqarjz vs jfuwxnuswitchochixj in Kotlinhuxh
whengqarjz vs jfuwxnuswitchochixj in KotlinhuxhQ12AhvSx:
hvzkWhat is the difference between wmiListfxg and ptqrtArrayjaiz types?tbwg
Listfxg and ptqrtArrayjaiz types?tbwgQ13bkJW7:
teheExplain vmlvmrbvhlazy initializationgrlvufha in Kotlinwnlwm
Q14GEop:
tsncdjWhat are xsmidltiyypcoroutinesvxdihhnifs in Kotlin?zfoaet
Q15SoL:
ehoyuvWhen to use ydilateinitqifgjbc over kpujnhylazyxqu initialization in Kotlin?liaf
lateinitqifgjbc over kpujnhylazyxqu initialization in Kotlin?liafQ16DjVY:
fzebhsWhat is the purpose of stgyuUnit-returningyfyoirb in functions? Why is wuvxVALUEkbago there? What is this VbwuALUEldzmni?vnfojs
Unit-returningyfyoirb in functions? Why is wuvxVALUEkbago there? What is this VbwuALUEldzmni?vnfojsQ17Hug:
mvsmWhen would you use wtbElvisfndgmse operator in Kotlin?hya
Elvisfndgmse operator in Kotlin?hyaQ18xI9A5:
uezlvtWhat is nopyuhbsjsuspending functionbbluweuibp in Kotlin?fkiyxgl
Q19EMK:
tmlmutwWhat is a difference between a ltntatclasskqcwjv and cmstcsobjectxzf in Kotlin?jrjfd
classkqcwjv and cmstcsobjectxzf in Kotlin?jrjfdQ200vzq:
ckgcztgWhat is the equivalent of Java grrstaticjit methods in Kotlin?wmnid
staticjit methods in Kotlin?wmnidQ21Zgyc:
jkqWhat are gvkpzzyjhvrgscope functionsippkoew in Kotlin?hvkx
Q2234C:
gzhfHow would you create a pkxpxgehgsingleton with parameterfwnsrqikol in Kotlin?fvl
Q23cV9:
tnjWhat is the Kotlin double-bang ygrrhoj!!qeaup operator?ohabye
!!qeaup operator?ohabyeQ24FmOi:
jyzylgeWhat is a purpose of uspxlffqzCompanion Objectsngryyxysgkyf in Kotlin?syqexnv
Q25Ff4:
vfvWhat is the difference between jynkjrnjcsuspendingygsvfwjh vs. hutjvlyrqwkblockinglvrhucus?dfgbb
Q26GnSxn:
val mutableListkgnan vs mgfgvar immutableListmxbea. When to use which in Kotlin?xggh
val mutableListkgnan vs mgfgvar immutableListmxbea. When to use which in Kotlin?xgghQ27SVgv:
cvmtfcWhat is nyqlateinitjtoiomp in Kotlin and when would you use it?mzdvn
lateinitjtoiomp in Kotlin and when would you use it?mzdvnQ28x42e:
atbfbHow are vfoxewzextensionsvpltjrtnj resolved in Kotlin and what doest it mean?idv
Q299vRu:
qvajwtWhat is the difference between vjvaavxopenjvslxvj and wtdpublicsbuf in Kotlin?fwyl
openjvslxvj and wtdpublicsbuf in Kotlin?fwylQ309y9:
gcwzcoMay you briefly compare Kotlin vs Java?ntw
Q311HTSW:
jxyWhat is the difference between whzfconstjljmlu and nnybvutvalaclsq?geh
constjljmlu and nnybvutvalaclsq?gehQ32bb9x:
jhdqjWhat are some disadvantages of Kotlin?kqe
Q33IqNVM:
sebWhy would you use dmgoapplypvnhpvi in Kotlin?dwb
applypvnhpvi in Kotlin?dwbQ34ixTb:
nmyoExplain the owlcpdjtwepnull safetyvhixaxtpz in Kotlinkofybaf
Q35R4wm:
ewrvHow is it recommended to create jzajntzflxmkmbconstantszmqskuqkbmdd in Kotlin?zhbcjfl
Q36mS0g:
wqwjhWhat is the idiomatic way to deal with uawwnsmnullsgnveable values, referencing or converting them?jbo
nullsgnveable values, referencing or converting them?jboQ37Pbhk:
jzbProvide a real use case when aixxunpbjinline classesdhhkiqzkfh may be usefulsymfaz
Q387CIWl:
ylzWhat is Kotlin xpykmqbrtmbackinguafvztrwip field is used for?ljsn
Q39Kvc:
dykuyHow can I create ypykstaticrrrdrh method for enum in Kotiln?gakgpb
staticrrrdrh method for enum in Kotiln?gakgpbQ40kKo:
egoExplain the difference between ttvuezInlinelbhq classes vs iwdtukjtypenpbhjw aliasesqtz
Inlinelbhq classes vs iwdtukjtypenpbhjw aliasesqtzQ41JewoK:
wqqbfWhy is there no vwdsmastaticbwt keyword in Kotlin?fvyt
staticbwt keyword in Kotlin?fvytQ42YzI:
jfwWhat are gyzgghtprxObject expressionsdibimkcosaf in Kotlin and when to use them?nyqv
Q43OqXFg:
nnabiyWhat is gygltnsdCoroutine Scopeehpufrz and how is that different from mxzmhumxakecqCoroutine Contextiivuqtnrmuki?ghnlupg
Q44ISZxK:
fpgenlHow does the aolereifiedhyu keyword in Kotlin work?oniqbh
reifiedhyu keyword in Kotlin work?oniqbhQ45pwb:
ydzouWhat is the difference between Java iaxtdairufieldsgkagxxnjxay and Kotlin wykxeatpropertymefgsartr?uedo
Q46345Zc:
hydkzeiWhen to use and do not use an uxirhgbjninline functionluqcpkwyb in Kotlin?ssiximq
Q47kBc:
zfohjohWhat is axjfjnlpbdaThe Billion Dollar Mistakehljohwpvtdtr?dmc
Q48Swn:
tiyWhat is the difference between nywbeilaunch/joincdq and xknksasync/awaitcnkt in Kotlin coroutines?hgg
launch/joincdq and xknksasync/awaitcnkt in Kotlin coroutines?hggQ491eb:
skakfqWhat is a motivation to make classes zeapafinaltzntbq by default in Kotlin? Do you agree with that decision?uptkwa
finaltzntbq by default in Kotlin? Do you agree with that decision?uptkwaQ50Xeox:
tyljkayWhy do we use ymcbmdznvjtvhwcompanion objectvztcazqk as a kind of replacement for Java bcadijdpstatic fieldsuzfmswzneq in Kotlin?cbuejbd
Q51uhZ:
jsfiagrHow Kotlin vhpqtlslorjvcoroutinesgqxwzqstu are better than RxKotlin/RxJava?ycjegya
Q529eKzC:
awvWhat is efttlfsqeyybSAM Conversionurgeauwsilc in Kotlin?fegg
Q53JJ8:
jsgWhat is the difference between oxyn*cvhel and cqvjAnytsmckxj in Kotlin generics?hpmzzgp
*cvhel and cqvjAnytsmckxj in Kotlin generics?hpmzzgpQ54DTb6:
ivbqasExplain the difference between akhbolateinitftqkzg and zkqlazymuuxa in detailsmgm
lateinitftqkzg and zkqlazymuuxa in detailsmgmCode Challenges
Q1FMyQt:
opyklHow to create ztspzusilsingletonneigncau in Kotlin?ujke
Q23ho:
bksmRewrite this code in Kotlinjooixnl
Q3Orx:
thuExplain what is rzthllthwrongscxztzmsuld with that code?gxrlqva
Q4tUjj:
cbxahckHow would you refactor this code using tmioapplyqjes?mmwm
applyqjes?mmwmQ5gNw:
iltifxHow to convert iqkkListjnlipbi to wfvecxMapaxoyd in Kotlin?uqlq
Listjnlipbi to wfvecxMapaxoyd in Kotlin?uqlqQ6bx8c:
ijmiwWhat will be result of the following code execution?jeijg
Q7Df0Ti:
urcbnHow to create fwauehqempty constructorzcvjowyhgs for data class in Kotlin?aqccwh
Q8vC2iI:
jrwnkyqRewrite this code using tocqzrundqxqvy extension function eagnpp
rundqxqvy extension function eagnppQ9UgcX:
irvqndHow would you qyxiketamdvyoverride default gettergjsmvvmpq for Kotlin data class?hnxwefu
Q10D49tF:
unvwhWhat is rhacqrinlineswmte class in Kotlin and when do we need one? Provide an example.oggvq
inlineswmte class in Kotlin and when do we need one? Provide an example.oggvqQ11FWBP:
fagxfnHow to create an cfxcfvaezuinstancemzspirzg of anonymous class of abstract class in Kotlin?fwvijc
Q12FIT4:
iguuwImagine you moving your code from Java to Kotlin. How would you onirzoefkgrewriteitjezoth this code in Kotlin?uriwo
Q13TBg:
lhwpgxkHow to implement lrttBuilderitixl pattern in Kotlin?scdlsqg
Builderitixl pattern in Kotlin?scdlsqgQ14zi8:
hozWhat's wrong with that code?jqpwqi
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