This list gather common resources for self testing his knowledge or preparing a Java interview. It is not meant to be exhaustive and is rather for my personal use.
I will took no responsibility of any kind about using the below information, that might sometimes be false or deprecated. (You should contact me or send a pull request if you see errors or have interesting additional resources to suggest).
- Hacker Rank: A nice web site with tutorials and corrected exercises to master the interviews
- Programmer interview questions
- Some Regex challenges
- A large source a Math / Algorithm problems: Project Euler
- Quite painful to read because of the ads and blinking style, yet a handful of interesting questions
- 3 list of various short question/answers that cover a wide spectrum of potential basic questions: core 1, core 2 and core 3 (the most interesting). Note that some answers might be kind of wrong, typically out-dated when talking about Java8+... Do not take all provided answers as granted and rather refer to corresponding documentation or tutorial to double check if you do not now the answer.
- Various types of collections
- Difference between a set and list
- Difference between heap and stack memory
- Give an example of what could lead to a high CPU usage
- Describe how Garbage collection works
- Speak about the equals and hash methods of the Object class
- What is the volatile key word used for
- List and define the method access level modifiers
- what is synchronisation and how will you implement it
- Difference between a synchronised method and block
- Difference between interface and abstract classes
- Talk about generics
- Difference between check and unchecked exceptions
- Where can one use the final key word and why
- Describe some of the highest challenges you ever faced and the strategies you had to solve them.
Quality FAQs gather a lot of question that one can asks himself and thus that can also be asked by an interviewer. It's worth reading them and trying to answer the questions before checking the provided answer
- A very complete FAQ about Generics by A. Langer