Backend Developer interview questions (2428)

200 questions

• What are the JDK, JRE and JVM, and how do they relate?

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• What are the Java primitive types and their default values?

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• What does the static keyword do in Java?

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• What is the string pool, and why are strings immutable?

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• What is the difference between an array and an ArrayList?

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• What are List, Set and Map, and when do you pick each?

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• What is the difference between String, StringBuilder and StringBuffer?

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• What does the final keyword do on variables, methods and classes?

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• What is a constructor, and how does constructor chaining with this() and super() work?

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• What is a Java package, and how does import work?

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• What is garbage collection in Java, and can you force it?

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• What are Java enums, and what can they contain?

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• How do you compile and run a Java program from the command line?

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• What is autoboxing and unboxing, and what are its pitfalls?

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• What causes StackOverflowError, and how is it different from OutOfMemoryError?

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• What are the Java access modifiers?

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• What is the Object class, and which methods does every Java object have?

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• What are the main features of Java as a language and platform?

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• What is the difference between local, instance and static variables?

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• What are the most used String methods, and how does immutability affect them?

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