api: mark getItemDefinition as nonnull

runelite-api/src/main/java/net/runelite/api/Client.java

@@ -29,6 +29,7 @@ import java.awt.Dimension;
 import java.util.EnumSet;
 import java.util.List;
 import java.util.Map;
+import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 import net.runelite.api.annotations.VisibleForDevtools;
 import net.runelite.api.coords.LocalPoint;
@@ -346,6 +347,7 @@ public interface Client extends GameEngine
 	 * @return the corresponding item composition
 	 * @see ItemID
 	 */
+	@Nonnull
 	ItemComposition getItemDefinition(int id);
 
 	/**

runelite-client/src/main/java/net/runelite/client/game/ItemManager.java

@@ -38,6 +38,7 @@ import java.util.Map;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.TimeUnit;
+import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 import javax.inject.Inject;
 import javax.inject.Singleton;
@@ -363,6 +364,7 @@ public class ItemManager
 	 * @param itemId item id
 	 * @return item composition
 	 */
+	@Nonnull
 	public ItemComposition getItemComposition(int itemId)
 	{
 		assert client.isClientThread() : "getItemComposition must be called on client thread";