feat: migrate to JSpecify

[TheMrMilchmann]

See #1008 for a detailed description.

Key changes:

• All occurrences of javax.annotation.Nullable have been replaced with org.jspecify.annotations.Nullable
  • This introduced a conceptual change as nullability effectively becomes a use-site attribute of the type. Where a method previously returned "String or null", it now returns a "nullable String". To reflect this, the location of the marker annotation was (an in a few cases had to be) changed.
  • @Nullable public static Something.Buffer ... becomes public static Something.@Nullable Buffer ...
  • The @Nullable marker now directly precedes the type before the @NativeType annotation where applicable.
• Likewise, org.lwjgl.system.NonnullDefault has been removed and replaced with org.jspecify.annotations.NullMarked.

This is a draft PR for the following reasons:

1. We need to decide whether we want to expose JSpecify as an API dependency. JSpecify recommends this, but using them as compile-only dependencies (just like we currently do with JSR305 annotations) would also work fine.
2. I'm not fully happy with the changes to the generator. If you have a better idea, please let me know.

[TheMrMilchmann]

This is the only use of JSR305 annotations that can't be replaced with JSpecify. We could keep JSR305 just for that but I figured it's not worth it.

[Spasi]

Great job @TheMrMilchmann, thanks!

[SWinxy]

Is it valid syntax to have a type, the annotation, and then .Buffer?

lwjgl3/modules/lwjgl/assimp/src/generated/java/org/lwjgl/assimp/AIBone.java

Line 235 in 2607557

public static AIBone.@Nullable Buffer createSafe(long address, int capacity) {

[TheMrMilchmann]

Is it valid syntax to have a type, the annotation, and then .Buffer?

lwjgl3/modules/lwjgl/assimp/src/generated/java/org/lwjgl/assimp/AIBone.java

Line 235 in 2607557

public static AIBone.@Nullable Buffer createSafe(long address, int capacity) {

@SWinxy This is not just valid, but the only correct syntax for the TYPE_USE syntax. In simple terms, these annotations must appear next to the concert type name (or []) they apply to. AIBone is just part of the qualifier for its nested Buffer. This is specified in JLS 9.7.4.

Some examples from JSpecify's docs (which apply to all TYPE_USE annotations):

1. For a nested static type like Map.Entry, if you want to say that the value can be null then the syntax is Map.@Nullable Entry. You can often avoid dealing with this by importing the nested type directly, but in this case import java.util.Map.Entry might be undesirable because Entry is such a common type name.

2. For an array type, if you want to say that the elements of the array can be null then the syntax is @Nullable String[]. If you want to say that the array itself can be null then the syntax is String @Nullable []. And if both the elements and the array itself can be null, the syntax is @Nullable String @Nullable [].

[SWinxy]

Wild! Thanks for the info.