[JENKINS-42934] Avoid using new FileInputStream / new FileOutputStream

core/src/main/java/hudson/ClassicPluginStrategy.java

@@ -23,6 +23,8 @@
  */
 package hudson;
 
+import java.io.InputStream;
+import java.nio.file.Files;
 import jenkins.util.SystemProperties;
 import com.google.common.collect.Lists;
 import hudson.Plugin.DummyImpl;
@@ -123,11 +125,8 @@ public class ClassicPluginStrategy implements PluginStrategy {
             try {
                 // Locate the manifest
                 String firstLine;
-                FileInputStream manifestHeaderInput = new FileInputStream(archive);
-                try {
+                try (InputStream manifestHeaderInput = Files.newInputStream(archive.toPath())) {
                     firstLine = IOUtils.readFirstLine(manifestHeaderInput, "UTF-8");
-                } finally {
-                    manifestHeaderInput.close();
                 }
                 if (firstLine.startsWith("Manifest-Version:")) {
                     // this is the manifest already
@@ -137,11 +136,8 @@ public class ClassicPluginStrategy implements PluginStrategy {
                 }
                 
                 // Read the manifest
-                FileInputStream manifestInput = new FileInputStream(archive);
-                try {
+                try (InputStream manifestInput = Files.newInputStream(archive.toPath())) {
                     return new Manifest(manifestInput);
-                } finally {
-                    manifestInput.close();
                 }
             } catch (IOException e) {
                 throw new IOException("Failed to load " + archive, e);
@@ -173,7 +169,7 @@ public class ClassicPluginStrategy implements PluginStrategy {
                         "Plugin installation failed. No manifest at "
                                 + manifestFile);
             }
-            try (FileInputStream fin = new FileInputStream(manifestFile)) {
+            try (InputStream fin = Files.newInputStream(manifestFile.toPath())) {
                 manifest = new Manifest(fin);
             }
         }