stub classes with classes

(cherry picked from commit 146e613)

(cherry picked from commit 8e1abfa)
(cherry picked from commit 26eacb9)

(cherry picked from commit 4403649)

(cherry picked from commit f98b427)

Author: deirn

src/apiPlatformStub/java/net/minecraftforge/fluids/FluidStack.java

@@ -3,12 +3,18 @@
 import net.minecraft.nbt.CompoundTag;
 import net.minecraft.world.level.material.Fluid;
 
-public interface FluidStack {
+public final class FluidStack {
 
-    Fluid getFluid();
+    public Fluid getFluid() {
+        throw new AssertionError("stub");
+    }
 
-    CompoundTag getTag();
+    public CompoundTag getTag() {
+        throw new AssertionError("stub");
+    }
 
-    int getAmount();
+    public int getAmount() {
+        throw new AssertionError("stub");
+    }
 
 }