diff --git a/src/main/java/com/jozufozu/flywheel/backend/gl/buffer/PersistentGlBuffer.java b/src/main/java/com/jozufozu/flywheel/backend/gl/buffer/PersistentGlBuffer.java
index 1a6b6f646..77dac7206 100644
--- a/src/main/java/com/jozufozu/flywheel/backend/gl/buffer/PersistentGlBuffer.java
+++ b/src/main/java/com/jozufozu/flywheel/backend/gl/buffer/PersistentGlBuffer.java
@@ -13,7 +13,6 @@ import com.jozufozu.flywheel.backend.gl.GlFence;
 import com.jozufozu.flywheel.backend.gl.error.GlError;
 import com.jozufozu.flywheel.backend.gl.error.GlException;
 import com.jozufozu.flywheel.util.StringUtil;
-import com.jozufozu.flywheel.util.Unimplemented;
 
 
 public class PersistentGlBuffer extends GlBuffer implements Mappable {
@@ -69,7 +68,7 @@ public class PersistentGlBuffer extends GlBuffer implements Mappable {
 
 	@Override
 	public void upload(ByteBuffer directBuffer) {
-		throw new Unimplemented("FIXME: Nothing calls #upload on a persistent buffer as of 12/10/2021.");
+		throw new UnsupportedOperationException("FIXME: Nothing calls #upload on a persistent buffer as of 12/10/2021.");
 	}
 
 	@Override
diff --git a/src/main/java/com/jozufozu/flywheel/util/Unimplemented.java b/src/main/java/com/jozufozu/flywheel/util/Unimplemented.java
deleted file mode 100644
index 0743ddc4c..000000000
--- a/src/main/java/com/jozufozu/flywheel/util/Unimplemented.java
+++ /dev/null
@@ -1,7 +0,0 @@
-package com.jozufozu.flywheel.util;
-
-public class Unimplemented extends RuntimeException {
-	public Unimplemented(String message) {
-		super(message);
-	}
-}