4 ms·

var is inside jdk10... http://openjdk.java.net/jeps/286 http://openjdk.java.net/jeps/286

• trzmiel4 9y ago
  The problem is that "val" or "const" is not.
  • koolba 9y ago
    Besides the 6 extra chars, the difference between “final var foo = ...” and “val foo = ...”?
    • trzmiel4 9y ago
      Those "6 extra chars" mean more noise for human on the screen, it can lead to line wrapping or in other way harm the formatting, and last but not least it does not make it easier to promote good coding practices.
      • ygra 9y ago
        If the final keyword hadn't existed before I'd agree, but it does exist, does exactly what you'd expect it to here, and I'd argue that since it's consistent with how it used to work, is actually easier to understand and grasp. Local type inference is a new feature. Locals that can be assigned once is not and people are already familiar with how such locals are declared. And there's no ambiguity which variant is the correct one, e.g.: var i = 0; final var i = 0; int i = 0; final int i = 0; val i = 0; One of the options there is a very odd one. And if there was "val", would "final var" be disallowed?
    • charriu 9y ago
      None of course, but I think that's the point of the complaint. For a feature supposed to increase convenience, it didn't go as far as it could have. Still, I'm glad var is in there. (Now, my employer just needs to get off of Java 8...)
      • merb 9y ago
        be carful with adopting java9 and java10. they won't live that long...
    • Hasknewbie 9y ago
      I would argue it's not about the extra characters, it's about enforcing explicit mutability. In Scala, where var/val both exist, each time you declare a variable you are forced to think about its mutability. But if you only have "var", with the _option_ of tacking "final" to it, then a programmer can simply forget to make that decision, because the language allowed them to.
    • deleted 9y ago
      [deleted]
• ygra 9y ago
  I think they meant the separate keywords to distinguish "var" and "final var". Personally I like just reusing the final keyword, which for once would actually mean the very same thing in the very same place, with "var" just taking place of the type name. More familiarity, less surprises.
• chrislynch42 9y ago
  var seems like a bad idea to me. One of the things I like about Java is (strong?) typing. Recently learning C# and was put off by 'var'. Why is it a good idea?
  • merb 9y ago
    depends, writing something like: `Simple<List<Map<String, Demo>, OtherList<Map<Int, String>>` is a little bit painful. I use scala and basically most often at least public Methods should (in scala you can omit even that, however some functional libraries need a return type) have a explicit type, which most often is enough.
  • ceronman 9y ago
    'var' in C# and Java doesn't change strong or static typing at all. It's just type inference. Your code is still statically typed, the compiler and IDE will catch errors. It's just that it's smart enough to infer the types of redundant things instead of making you type it. So instead of typing: AbstractConcreteFactoryFactory factory = new AbstractConcreteFactoryFactory(); You can just type it only once: var factory = new AbstractConcreteFactoryFactory();
  • pjmlp 9y ago
    Variables declared with var are still strongly typed. Just because the keyword exists in JavaScript, it doesn't mean it has the same semantic meaning. var p = new Person(); p = 1234; // This will trigger a compile time error
  • bpicolo 9y ago
    It drastically decreases mental/physical overhead of typing the dang code out without in any way affecting typing. C# is a huge breath of fresh air compared to java largely because of useful type inference. It's easy to make compilers do more work now. Rust is doing type inference with drastically stronger types, for example.