Java Topics
HubJava Collections FrameworkCollections Practice ProgramsComparable vs ComparatorGenericsIteratorArrayListLinkedListStackVectorHashMapHashtableLinkedHashMapTreeMapArrayDequeDeque Double-Ended QueuePriorityQueueHashSetLinkedHashSetTreeSetAdapter PatternBuilder PatternFactory PatternMVC PatternObserver PatternSingleton PatternDynamic ProgrammingGraphHashingHeapLinked List DSAQueue DSARecursionSearching AlgorithmsSorting AlgorithmsStack DSATime ComplexityTreesException Handling Best PracticesCustom ExceptionException Hierarchyfinally BlockException Handlingthrow aur throwstry-catchBuffered StreamsByte StreamsCharacter StreamsDeserializationFile ClassJava NIO New I/OSerializationArrays in JavaArray OperationsArray Practice ProgramsArray Interview QuestionsJagged ArrayMulti-Dimensional ArraysOne Dimensional Arraybreak aur continuedo-while Loopfor Loopif-else StatementsNested Loopsswitch-case Statementwhile LoopJava Compilation ProcessJava ki FeaturesPehla Java ProgramHistory of JavaJava EditionsJava Program StructureJDK, JRE aur JVMJava Kya Hai?Immutable StringsString Class in JavaString Interview QuestionsString MethodsString Practice ProgramsStringBufferStringBuilderComments in JavaData Types in JavaIdentifiers in JavaInput & Output in JavaJava KeywordsOperators in JavaType Casting in JavaVariables in JavaJava Coding Interview QuestionsCollections Interview QuestionsCore Java Interview QuestionsJDBC Interview QuestionsMultithreading Interview QuestionsOOPs Interview QuestionsSpring Framework Interview QuestionsJava 8 Date/Time APIDefault aur Static Methods in InterfaceFunctional InterfaceLambda ExpressionMethod ReferenceOptional ClassStream APIBatch ProcessingCallableStatementJDBC ArchitectureJDBC — Java Database ConnectivityJDBC Practice ProjectsMySQL ConnectionPreparedStatementResultSetStatement InterfaceTransaction ManagementCreating ThreadsDaemon ThreadExecutor FrameworkInter-Thread CommunicationMultithreading Practice ProgramsRunnable InterfaceSynchronizationThread ClassMultithreading IntroductionThread Life CycleThread PriorityJava Cheat SheetImportant Formulas & Key ConceptsImportant Java ProgramsJava Quick RevisionAbstract ClassAbstractionAnonymous ClassClass and ObjectConstructorEncapsulationInheritanceInner ClassInterfaceMethod OverloadingMethod OverridingObject ClassObject CloningObject-Oriented Programming OOPPolymorphismstatic Keywordsuper Keywordthis KeywordWrapper ClassesArray Practice ProgramsBasic Java Practice ProgramsCollection Practice ProgramsJDBC Practice ProgramsMultithreading Practice ProgramsOOPs Practice ProgramsPlacement Coding QuestionsString Practice ProgramsBanking SystemChat ApplicationE-Commerce Backend — Spring Boot REST APIEmployee Management SystemLibrary Management SystemSpring Boot Fullstack ProjectStudent Management SystemCookies in ServletExpression Language ELGenericServletHttpServletJavaServer Pages JSPJSP TagsMVC ArchitectureHttpServletRequest & HttpServletResponseServlet IntroductionServlet Life CycleSession TrackingDependency InjectionSpring BeansSpring CoreSpring FrameworkAPI GatewaySpring Cloud Config ServerDocker DeploymentEureka Server — Service DiscoverySpring Boot CRUD ApplicationException Handling in Spring BootJWT AuthenticationREST API in Spring BootSpring SecuritySpring BootSpring Data JPAValidation in Spring Boot
Array Interview Questions
Last Updated : 26 May, 2026
title: Array Interview Questions
Fundamentals119 words6 headingsTables includedExamples included
title: Array Interview Questions description: Arrays ke important interview questions
Q1. Array aur ArrayList mein kya fark hai?
| Array | ArrayList | |
|---|---|---|
| -- | -- | -- |
| Size | Fixed | Dynamic |
| Type | Primitive + Object | Sirf Object |
| Performance | Fast | Thoda slow |
| Methods | Limited | Many |
Q2. Time Complexity of Array Operations?
- Access by index: O(1)
- Search (unsorted): O(n)
- Search (sorted, binary): O(log n)
- Insert/Delete at end: O(1)
- Insert/Delete at middle: O(n)
Q3. 2D array memory mein kaise store hota hai?
Row-major order mein — pehli poori row, phir doosri row, etc.
Q4. Array mein missing number dhundho (1 to N)
java exampleWoHoTech
int findMissing(int[] arr, int n) {
int expected = n * (n + 1) / 2;
int actual = 0;
for (int x : arr) actual += x;
return expected - actual;
}Q5. Array mein majority element dhundho (Moore's Voting)
int majorityElement(int[] arr) {
int candidate = arr[0], count = 1;
for (int i = 1; i < arr.length; i++) {
if (count == 0) { candidate = arr[i]; count = 1; }
else if (arr[i] == candidate) count++;
else count--;
}
return candidate;
}
Q6. Dutch National Flag Algorithm (0,1,2 sort)
void sort012(int[] arr) {
int lo = 0, mid = 0, hi = arr.length - 1;
while (mid <= hi) {
if (arr[mid] == 0) swap(arr, lo++, mid++);
else if (arr[mid] == 1) mid++;
else swap(arr, mid, hi--);
}
}
Exam Focus
Revise definitions, diagrams, examples, and short-answer points for Array Interview Questions.
Interview Use
Prepare one clear explanation, one practical example, and one common mistake for this Java topic.
Search Terms
java, java programming, core java, java master course, java notes, master, course, fundamentals
Related Java Topics
Continue learning this concept
FundamentalsString Interview Questionstitle: String Interview QuestionsFundamentalsArrays in Javatitle: Array IntroductionFundamentalsArray Operationstitle: Array OperationsFundamentalsArray Practice Programstitle: Array ProgramsFundamentalsJagged Arraytitle: Jagged Array in JavaFundamentalsMulti-Dimensional Arraystitle: Multi Dimensional Array