Java: Out with the Old, In with the New

Question

Java is nearing version 7. It occurs to me that there must be plenty of textbooks and training manuals kicking around that teach methods based on older versions of Java, whe

Answer 1

Older code using Thread instead of the many other alternatives to Thread... these days, very little of the code I run across still needs to use a raw thread. They would be better served by a level of abstraction, particular Callable/Futures/Executors.

See:

java.util.Timer

javax.swing.Timer

java.util.concurrent.*

Answer 2

String comparisons, really old school Java programmers I've met would do:

String s1 = "...", s2 = "...";

if (s1.intern() == s2.intern()) {
    ....
}

(Supposedly for performance reasons)

Whereas these days most people just do:

String s1 = "...", s2 = "...";

if (s1.equals(s2)) {
    ....
}

Answer 3

New version of Java rarely break existing code, so just leave old code alone and focus on how the new feature makes your life easier.

If you just leave old code alone, then writing new code using new features isn't as scary.

Answer 4

Q1: Well, the most obvious situations are in the generics / type specific collections. The other one that immediately springs to mind is the improved for loop, which I feel is a lot cleaner looking and easier to understand.

Q2: In general, I have been bundling the JVM along side of my application for customer-facing apps. This allows us to use new language features without having to worry about JVM incompatibility.

If I were not bundling the JRE, I would probably stick to 1.4 for compatibility reasons.

Answer 5

Okay, now it's my turn to get yelled at.

I don't recommend 90% of these changes.

It's not that it's not a good idea to use them with new code, but breaking into existing code to change a for loop to a for(:) loop is simply a waste of time and a chance to break something. (IIWDFWI) If it works, don't fix it!

If you are at a real development company, that change now becomes something to code-review, test and possibly debug.

If someone doing this kind of a refactor for no reason caused a problem of ANY sort, I'd give them no end of shit.

On the other hand, if you're in the code and changing stuff on that line anyway, feel free to clean it up.

Also, all the suggestions in the name of "Performance" really need to learn about the laws of optimization. In two words, Don't! Ever! (Google the "Rules of optimization if you don't believe me).

Answer 6

Using Swing's new DefaultRowSorter to sort tables versus rolling your own from scratch.