☕ Java Fundamentals — interview questions

12 questions. Filter by what the role asks for; open one for the six layers of the answer. The course is where the answers come from.

12 of 12

01What is the difference between the JDK, the JRE and the JVM?Platformeasy0-2y 02Is Java pass-by-value or pass-by-reference?Languagemedium0-2y 03What happens if you override equals() but not hashCode()?Languagemedium0-2y 04Why are strings immutable in Java, and what does that cost?Languageeasy0-2y 05What is the difference between int and Integer? Where does autoboxing bite?Languagemedium0-2y 06What changed in switch, and why should a sealed switch have no default?Languagemedium3-5y 07How are overloading and overriding resolved differently?Languagemedium0-2y 08Explain the access modifiers, and why package-private is a design tool.Designeasy0-2y 09Why is a Java service slower in its first minute after a deploy, and what do you do about it?Platformhard3-5y 10How do you read a stack trace with 90 framework frames in it?Debuggingeasy0-2y 11When is var appropriate, and what are text blocks for?Languageeasy0-2y 12How do you make a class immutable, and why does it matter?Designmedium0-2y