What is the point of the diamond operator (<>) in Java 7?

Question

The diamond operator in java 7 allows code like the following:

List list = new LinkedList<>();

However in Java 5/6, I c

Answer 1

In theory, the diamond operator allows you to write more compact (and readable) code by saving repeated type arguments. In practice, it's just two confusing chars more giving you nothing. Why?

1. No sane programmer uses raw types in new code. So the compiler could simply assume that by writing no type arguments you want it to infer them.
2. The diamond operator provides no type information, it just says the compiler, "it'll be fine". So by omitting it you can do no harm. At any place where the diamond operator is legal it could be "inferred" by the compiler.

IMHO, having a clear and simple way to mark a source as Java 7 would be more useful than inventing such strange things. In so marked code raw types could be forbidden without losing anything.

Btw., I don't think that it should be done using a compile switch. The Java version of a program file is an attribute of the file, no option at all. Using something as trivial as

package 7 com.example;

could make it clear (you may prefer something more sophisticated including one or more fancy keywords). It would even allow to compile sources written for different Java versions together without any problems. It would allow introducing new keywords (e.g., "module") or dropping some obsolete features (multiple non-public non-nested classes in a single file or whatsoever) without losing any compatibility.