Finish converting most of the undeprecated api to jspecify

patches/api/0444-Add-FluidState-API.patch

@@ -6,22 +6,23 @@ Subject: [PATCH] Add FluidState API
 
 diff --git a/src/main/java/io/papermc/paper/block/fluid/FluidData.java b/src/main/java/io/papermc/paper/block/fluid/FluidData.java
 new file mode 100644
-index 0000000000000000000000000000000000000000..913acd58547d97cafc1466f6e2b3b4d22cf0b02d
+index 0000000000000000000000000000000000000000..0750219fc68261e5c396636967e0b633ae17b72e
 --- /dev/null
 +++ b/src/main/java/io/papermc/paper/block/fluid/FluidData.java
-@@ -0,0 +1,68 @@
+@@ -0,0 +1,69 @@
 +package io.papermc.paper.block.fluid;
 +
 +import org.bukkit.Fluid;
 +import org.bukkit.Location;
 +import org.bukkit.util.Vector;
-+import org.jetbrains.annotations.NotNull;
 +import org.jetbrains.annotations.Range;
++import org.jspecify.annotations.NullMarked;
 +
 +/**
 + * A representation of a fluid in a specific state of data.
 + * This type is not linked to a specific location and hence mostly resembles a {@link org.bukkit.block.data.BlockData}.
 + */
++@NullMarked
 +public interface FluidData extends Cloneable {
 +
 +    /**
@@ -29,14 +30,14 @@ index 0000000000000000000000000000000000000000..913acd58547d97cafc1466f6e2b3b4d2
 +     *
 +     * @return the fluid type
 +     */
-+    @NotNull Fluid getFluidType();
++    Fluid getFluidType();
 +
 +    /**
 +     * Returns a copy of this FluidData.
 +     *
 +     * @return a copy of the fluid data
 +     */
-+    @NotNull FluidData clone();
++    FluidData clone();
 +
 +    /**
 +     * Computes the direction of the flow of the liquid at the given location as a vector.
@@ -48,7 +49,7 @@ index 0000000000000000000000000000000000000000..913acd58547d97cafc1466f6e2b3b4d2
 +     * @param location - the location to check the liquid flow
 +     * @return the flow direction vector at the given location
 +     */
-+    @NotNull Vector computeFlowDirection(@NotNull Location location);
++    Vector computeFlowDirection(Location location);
 +
 +    /**
 +     * Returns the level of liquid this fluid data holds.
@@ -69,7 +70,7 @@ index 0000000000000000000000000000000000000000..913acd58547d97cafc1466f6e2b3b4d2
 +     * @return the height as a float value
 +     */
 +    @Range(from = 0, to = 1)
-+    float computeHeight(@NotNull Location location);
++    float computeHeight(Location location);
 +
 +    /**
 +     * Returns whether this fluid is a source block