Java Questions

[skatcat31]

I was recently in an interview where I was asked "What is the difference between .equals and == when comparing Objects in Java?" that I thought would be a good example to highlight here. I do however want to think of the best way to go about it. To that end I've thought of two problems with it currently that should be addressed before submission:

• Should we expand this question to cover more languages?
• Should we consider this a Java specific question and host questions like it for other languages?

[skatcat31]

Expanding the question:

How would you compare two objects to check for different types of equality?

Equality can mean many things, but primarily in computer science there are two ways to check for equality with Objects:

• By Value
• By Reference

By Value

Checking equality by value means to see if the second Object stores an equivalent value. In Java this is done with the .equals method, and in JavaScript this is done with loose evaluation(==)

By Reference

Checking equality by reference means to see if the second Variable resolves to the same Object in memory. In Java this is done on Objects with == and in JavaScript with strictly equal to(===)

[skatcat31]

Otherwise the other option is to add tags for languages and put this as an example in each with the differences per language highlighted against a 'base' language(probably JavaScript since this is a full stack resource)

[fejes713]

Thanks for pointing this out @skatcat31

We have discussed this in the early days of 30 seconds of interviews and there were mixed opinions on this topic.

In general, this is a great idea. It makes sense to have different answers for different programming languages. However, our interview question database is not very big ~80 questions.

Personally, I am against adding material that is not in the scope of modern full-stack web development for now. Mainly because, as I said, we have ~80 questions and it is not worth it.