Java 8’s new Optional type doesn't solve anything

Re:Java 8’s new Optional type doesn't solve anything by mike_hearn on Monday October 26, 2015 @12:33PM (#10452474)

Much better than using static analysis is to have it in the type system:

It's simple:

val x: Foo = maybeGetSomeFoo() // Error: method returns Foo?

val x: Foo? = maybeGetSomeFoo()

x.sayHello() // Error: x may be null

x!!.sayHello() // OK, the !! method throws an exception if it's null

if (x != null) x.sayHello() // OK, flow sensitive typing means the test narrows the type

val h = x?.sayHello() // OK, ?. yields null if left hand side is null, otherwise evaluates right

val h = x?.sayHello() ?: return // OK, ?: runs right hand side only if left hand side is null

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Re:Java 8’s new Optional type doesn't solve anything by dllthomas on Tuesday October 27, 2015 @09:06PM (#10462300)

"Much better than using static analysis is to have it in the type system"

I am not sure there is a distinction. Though it is true that some analyses may be run by a broader swath of users.

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