System.out.println() vs \n in Java
There is a functional difference between the two. The first version outputs line breaks using the platform's preferred line separator. The second version outputs newline characters, which is likely to be inappropriate on Windows or Mac OS.
This is more important than any real or imagined performance advantages.
On the topic of performance, and why everyone seems to be saying "enough already".
The performance difference between your two ways of writing that code is likely to be a small number of microseconds, or less. In other words, an end user won't notice the difference ... unless the code is executed millions of times.
As a general rule, professional software engineers take the view that it is not worth spending time to make something faster if it doesn't need to be faster. And it is certainly not worth spending the client's money doing this.
You should only indulge in micro-optimization if you have clear evidence that there is, or will be a performance problem, and that the code that you are about to optimize is where the real problem is / will be. Time spent optimizing the wrong bit of code is time wasted.
So how do you know when to optimize?
- When the application is observably slow when measured against criteria that actually matter.
And how do you know what to optimize?
- By running application profilers, and analysing their output to see where the actual performance hotspots and bottlenecks are.
Performance is not always an unimportant issue. Indeed, for some kinds of software, a design or implementation that doesn't take account of performance and scalability requirements can be a total disaster. However, most software is not like that.
Perhaps better than either:
System.out.printf("%n%n%n%n%n");
That uses the line separator appropriate to your platform, where "\n" doesn't.