Fix possible resource leak and/or file locking errors: The file output

streams for the readme file and header file were not being closed.

src/main/java/org/apache/commons/release/plugin/SharedFunctions.java

@@ -50,7 +50,7 @@ private SharedFunctions() {
      *
      * @param log is the Maven log for output logging, particularly in regards to error management.
      * @param workingDirectory is a {@link File} that represents the directory to first attempt to delete then create.
-     * @throws MojoExecutionException when an {@link IOException} or {@link NullPointerException} is caught for the 
+     * @throws MojoExecutionException when an {@link IOException} or {@link NullPointerException} is caught for the
      *      purpose of bubbling the exception up to Maven properly.
      */
     public static void initDirectory(Log log, File workingDirectory) throws MojoExecutionException {

src/main/java/org/apache/commons/release/plugin/mojos/CommonsDistributionStagingMojo.java

@@ -298,32 +298,37 @@ private List<File> copyDistributionsIntoScmDirectoryStructure(File copiedRelease
     private List<File> buildReadmeAndHeaderHtmlFiles() throws MojoExecutionException {
         List<File> headerAndReadmeFiles = new ArrayList<>();
         File headerFile = new File(distCheckoutDirectory, "HEADER.html");
+        //
+        // HEADER file
+        //
+        try (Writer headerWriter = new OutputStreamWriter(new FileOutputStream(headerFile), "UTF-8")) {
+            HeaderHtmlVelocityDelegate.builder().build().render(headerWriter);
+        } catch (IOException e) {
+            final String message = "Could not build HEADER html file " + headerFile;
+            getLog().error(message, e);
+            throw new MojoExecutionException(message, e);
+        }
+        headerAndReadmeFiles.add(headerFile);
+        //
+        // README file
+        //
         File readmeFile = new File(distCheckoutDirectory, "README.html");
-        try {
-            FileOutputStream headerStream = new FileOutputStream(headerFile);
-            Writer headerWriter = new OutputStreamWriter(headerStream, "UTF-8");
-            FileOutputStream readmeStream = new FileOutputStream(readmeFile);
-            Writer readmeWriter = new OutputStreamWriter(readmeStream, "UTF-8");
-            HeaderHtmlVelocityDelegate headerHtmlVelocityDelegate = HeaderHtmlVelocityDelegate
-                .builder()
-                .build();
-            headerWriter = headerHtmlVelocityDelegate.render(headerWriter);
-            headerWriter.close();
-            headerAndReadmeFiles.add(headerFile);
-            ReadmeHtmlVelocityDelegate readmeHtmlVelocityDelegate = ReadmeHtmlVelocityDelegate
-                .builder()
-                .withArtifactId(project.getArtifactId())
-                .withVersion(project.getVersion())
-                .withSiteUrl(project.getUrl())
-                .build();
-            readmeWriter = readmeHtmlVelocityDelegate.render(readmeWriter);
-            readmeWriter.close();
-            headerAndReadmeFiles.add(readmeFile);
-            headerAndReadmeFiles.addAll(copyHeaderAndReadmeToSubdirectories(headerFile, readmeFile));
+        try (Writer readmeWriter = new OutputStreamWriter(new FileOutputStream(readmeFile), "UTF-8")) {
+            // @formatter:off
+            ReadmeHtmlVelocityDelegate readmeHtmlVelocityDelegate = ReadmeHtmlVelocityDelegate.builder()
+                    .withArtifactId(project.getArtifactId())
+                    .withVersion(project.getVersion())
+                    .withSiteUrl(project.getUrl())
+                    .build();
+            // @formatter:on
+            readmeHtmlVelocityDelegate.render(readmeWriter);
         } catch (IOException e) {
-            getLog().error("Could not build HEADER and README html files", e);
-            throw new MojoExecutionException("Could not build HEADER and README html files", e);
+            final String message = "Could not build README html file " + readmeFile;
+            getLog().error(message, e);
+            throw new MojoExecutionException(message, e);
         }
+        headerAndReadmeFiles.add(readmeFile);
+        headerAndReadmeFiles.addAll(copyHeaderAndReadmeToSubdirectories(headerFile, readmeFile));
         return headerAndReadmeFiles;
     }