Add NullReader.INSTANCE.

Author: Gary Gregory

src/changes/changes.xml

@@ -99,6 +99,9 @@ The <action> type attribute can be add,update,fix,remove.
       <action dev="ggregory" type="add" due-to="Gary Gregory">
         Add NullInputStream.INSTANCE.
       </action>
+      <action dev="ggregory" type="add" due-to="Gary Gregory">
+        Add NullReader.INSTANCE.
+      </action>
       <!-- UPDATE -->
       <action dev="ggregory" type="update" due-to="Dependabot">
         Bump Maven Javadoc plugin from 3.2.0 to 3.3.0.

src/main/java/org/apache/commons/io/input/NullReader.java

@@ -66,6 +66,13 @@
  */
 public class NullReader extends Reader {
 
+    /**
+     * The singleton instance.
+     *
+     * @since 2.12.0
+     */
+    public static final NullReader INSTANCE = new NullReader();
+
     private final long size;
     private long position;
     private long mark = -1;

src/test/java/org/apache/commons/io/test/ThrowOnCloseReader.java

@@ -30,9 +30,8 @@ public class ThrowOnCloseReader extends ProxyReader {
     /**
      * Default ctor.
      */
-    @SuppressWarnings("resource")
     public ThrowOnCloseReader() {
-        super(new NullReader());
+        super(NullReader.INSTANCE);
     }
 
     /**