Java coding interview practice

48 test-checked Java exercises for the live-coding interview: strings, collections, streams, records, sealed types and generics, compiled on JDK 21. Free.

Topics

• Strings
• Collections
• Streams & lambdas
• Records, classes & interfaces
• Generics & Optional
• Exceptions & validation
• Algorithms & recursion
• Modern Java

Each exercise pairs a worked example with a twin problem to solve in a real editor; the tests run the moment you do. Progress is saved in your browser, and in your account if you sign in.

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