8297750: Unnecessary Vector usage in IIORegistry

Reviewed-by: prr, serb

Author: Andrey Turbanov

src/java.desktop/share/classes/javax/imageio/spi/IIORegistry.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2022, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -27,12 +27,7 @@
 
 import java.security.PrivilegedAction;
 import java.security.AccessController;
-import java.util.HashMap;
 import java.util.Iterator;
-import java.util.Map;
-import java.util.NoSuchElementException;
-import java.util.Set;
-import java.util.Vector;
 import com.sun.imageio.spi.FileImageInputStreamSpi;
 import com.sun.imageio.spi.FileImageOutputStreamSpi;
 import com.sun.imageio.spi.InputStreamImageInputStreamSpi;
@@ -52,6 +47,7 @@
 import com.sun.imageio.plugins.tiff.TIFFImageReaderSpi;
 import com.sun.imageio.plugins.tiff.TIFFImageWriterSpi;
 import sun.awt.AppContext;
+import java.util.List;
 import java.util.ServiceLoader;
 import java.util.ServiceConfigurationError;
 
@@ -87,18 +83,16 @@
 public final class IIORegistry extends ServiceRegistry {
 
     /**
-     * A {@code Vector} containing the valid IIO registry
+     * A {@code List} containing the valid IIO registry
      * categories (superinterfaces) to be used in the constructor.
      */
-    private static final Vector<Class<?>> initialCategories = new Vector<>(5);
-
-    static {
-        initialCategories.add(ImageReaderSpi.class);
-        initialCategories.add(ImageWriterSpi.class);
-        initialCategories.add(ImageTranscoderSpi.class);
-        initialCategories.add(ImageInputStreamSpi.class);
-        initialCategories.add(ImageOutputStreamSpi.class);
-    }
+    private static final List<Class<?>> initialCategories = List.of(
+            ImageReaderSpi.class,
+            ImageWriterSpi.class,
+            ImageTranscoderSpi.class,
+            ImageInputStreamSpi.class,
+            ImageOutputStreamSpi.class
+    );
 
     /**
      * Set up the valid service provider categories and automatically