Saturday, February 25, 2006

Enhanced for Loop

The enhanced for loop introduced in JDK 1.5 makes it easier to loop through arrays and collections. However, as some of the other features added later in the evolution of the Java language, the enhanced for loop can behave unexpectedly.

For one, initializing array members within the enhanced for loop does not really initialize them. Thus, the following code

String[] sa = new String[2];
for(String s : sa) {
s = "hello";
}
for(String s : sa) {
System.out.println(s);
}

prints "null" twice instead of "hello". Despite of this pitfall, the enhanced for loop is a welcome addition.

Notwithstanding the purportedly increased safety they bring to the language, I can't say the same about generics. Java generics seem so much weaker and confusing than generics in the Ada language, where they are a core language feature, not an awkward afterthought.

Generics seem as one of those half-baked features capable of making the life of programmers miserable. With more experience, I hope my initial concerns about generics will reveal themselves to be unjustified.

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