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Updated weekly · Last refresh Sep 13

Top 50 java Interview Questions

The most frequently asked java questions across all roles and companies, ranked by real interview frequency. Updated daily.

50questions
~16htotal time
381companies covered
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1
CodingStart here. 41 questions · ~781 min
Find Duplicate Characters in StringEasy
Practice
Recently asked

Use a hash table to count character frequencies and return duplicate characters in first-appearance order.

Hash TablesjavaStringsPlayStationSt. Charles TradingChubb
Palindrome Number ImplementationEasy
Practice

Determine whether an integer reads identically forward and backward using digit arithmetic and constant extra space.

javaBasic AlgorithmsStringsBroadcomBrillioDeutsche Bank
Optimized Prime Number CodeMedium
Practice

Determine whether an integer is prime using square-root bounds and parity-based optimization.

javaPrincipal Financial GroupTavant
Reverse Words in a SentenceMedium
Practice
Recently asked

Reverse each word independently while preserving whitespace characters, runs, positions, and word order.

javastring manipulationArray ManipulationTripadvisor
Deep Clone Nested StructuresHard
Practice

Implement deep cloning for nested arrays and objects using recursion and cycle detection.

RecursionjavaabstractionMcKinsey &
Linked List and Graph/Tree CodingEasy
Practice

Detect a cycle in a Design Compiler dependency chain using linked-list pointers or graph traversal.

multithreadingjavaData StructuresMicro1Synopsys
Immutable vs Mutable ClassesMedium
Practice
Recently asked

Design an immutable Employee that safely encapsulates a separately mutable Address through defensive copying.

javaGloballogic
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2
Behavioral & Leadership6 questions · ~114 min
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3
More topics3 questions · ~57 min
SQL Queries for RankingMedium
Practice

Rank active HSBC employees by division and return every employee tied for the highest or second-highest salary.

javasqlHsbc
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Hands-on SQL practiceWrite and run real queries in the editor. 2 drills · ~20 min
The finish line: interview-readyComplete all 50 questions plus 2 hands-on drills to finish this plan.