I've been interviewing candidates for senior Java developer positions, and I've noticed a concerning trend: many developers, despite having over 8 years of experience, don't grasp that Java uses pass-by-value when it comes to method arguments. For instance, take a look at this simple code snippet:
```java
String x = "abc";
change(x);
System.out.println(x); // what is printed?
private void change(String a) {
a = "xyz";
}
```
When I posed this question, the last three candidates all incorrectly believed it would print "xyz". It's surprising given their level of experience! One candidate correctly stated that Java passes by value and explained that a copy is made, yet they still failed the follow-up question. Overall, it leaves me in doubt on whether to hire them or not. Shouldn't such a fundamental concept be firmly understood at this stage of their careers?
5 Answers
I think it’s a valid question but also one that requires context. As developers, we evolve past certain fundamentals in our daily work. If they can't discuss key concepts when stressed, that’s concerning. However, I think better context in the question might yield different responses. Maybe prompting them to expand on how other objects and types behave could bring out more insight.
It's definitely alarming that experienced developers don't understand this. I've encountered serious bugs caused by developers who mishandle variable scopes and references. If they're struggling with a fundamental concept like this, I'd say they might not be the best fit for a senior role. It's crucial that they can reason about how method parameters affect program state, especially in a language like Java.
Agreed! It’s all about understanding those core principles. I've seen similar issues arise in production as well, so not being able to articulate this could be a red flag. They should definitely grasp how parameters work at their level.
Honestly, I wouldn't hire them based on this misstep. This is a fundamental concept for any Java developer. If they've worked with Java for several years and still can't explain how it handles method parameters, it shows a concerning lack of depth in their understanding.
Right? It makes you wonder about their overall coding skills. This kind of basic knowledge should be second nature for someone in that position.
While I see why you'd be concerned, I've also been on the receiving end of similar 'trick' questions, and they can be more confusing than illuminating. Many good developers can overlook nuanced theoretical points under pressure. Still, not knowing it at all? That's a different story. I'd expect them to at least know the basics of how Java handles parameters regardless of their specific phrasing.
True, but knowing basic Java semantics isn't just trivia; it's foundational. If they can’t articulate how Java works, they might struggle with more complex coding challenges.
It’s also worth mentioning that some candidates might not connect the theory with practical coding experience. I wonder if part of it comes from a trend where developers focus more on frameworks than the underlying language fundamentals. It's a shame because this knowledge helps in debugging and writing robust code.
Exactly! Relying solely on frameworks without understanding the core language leads to these gaps. It’s really about building a solid foundation before trying to construct the skyscraper!
That makes sense! This question could definitely be refined. It's quite possible they might understand the concept but still get flustered in interviews.