What if null was an Object in Java?
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What if null was an Object in Java?
1–10 of 164 posts
Re: What if null was an Object in Java?
#2I totally support the idea of null having type Null, but only if null no longer has type Integer, and null no longer has type Bufferedreader, etc.
Re: What if null was an Object in Java?
#3Doesn't an Optional basically cover this case
Re: What if null was an Object in Java?
#4I don't actually think it solves any problems. You still have to null check.
Re: What if null was an Object in Java?
#5If Null is not a subtype of MyType, then you wouldn't be able to assign null to a variable decalred as MyType, without breaking the rest of the rules of Java. I don't really see how this could work, even theoretically.
Re: What if null was an Object in Java?
#6If Null is not a subtype of MyType, then you wouldn't be able to assign null to a variable decalred as MyType, without breaking the rest of the rules of Java. I don't really see how this could work, even theoretically.
There's no reason that something can't both an object and the bottom of the type hierarchy.
It's, technically, an instance of multiple inheritance. Java doesn't generally allow this, but there's tons of special cases in the compiler for things that you can't do yourself. For example, defining operators is done in the compiler, but you can't define operators for your own classes.
Re: What if null was an Object in Java?
#7I think the nullable reference type system in c# is a perfectly workable compromise for languages that had nullability from the very beginning. Once a code base uses them fully, most null-related bugs are gone. And it’s far from an unwieldy bolt-on.
Re: What if null was an Object in Java?
#8Doesn't an Optional basically cover this case
An Optional is just a tri-valued null (null, None, and Some), so no.
It'd be nice if Java had a concept of a never-null reference (like a C++ reference vs. a C++ pointer), but the @NotNull annotation wasn't enforced the last time I checked.
Also, there's no way for an object to express that invariant because encapsulation is so weak. Given only this constructor (and no reflection):
Foo() { foo.bar = new Bar(); /* foo.bar is final; Bar() does not throw */ }
Anyway, null handling in java somehow manages to be worse than C, where you can at least inline a struct into another, statically guaranteeing the instance of the inlined struct exists.
I can't think of another statically typed language that screws this up so badly. It just keeps getting worse with stuff like Optional and @NotNull.
(Disclaimer: I haven't followed java for 4-5 years; it's possible they finally fixed this stuff.)
Re: What if null was an Object in Java?
#9Doesn't an Optional basically cover this case
An Optional is just a tri-valued null (null, None, and Some), so no. It'd be nice if Java had a concept of a never-null reference (like a C++ reference vs. a C++ pointer), but the @NotNull annotation wasn't enforced the last time I checked. Also, there's no way for an object to express that invariant because encapsulation is so weak. Given only this constructor (and no reflection): Foo() { foo.bar = new Bar(); /* foo…
Fortunately, Uber made tooling for languages with broken type systems
Re: What if null was an Object in Java?
#10Ruby has a `NilClass` and the best/worst part of it is the to_s is "", to_i is 0, to_f is 0.0, to_a is [], to_h is {}
It's incredibly clean and convenient until you wake up one morning and have no idea what is happening in your code