src/java.base/share/classes/java/util/jar/JarFile.java

@@ -26,10 +26,11 @@
 package java.util.jar;
 
 import java.io.*;
 import java.lang.ref.SoftReference;
 import java.net.URL;
+import java.nio.ByteBuffer;
 import java.util.*;
 import java.util.stream.Stream;
 import java.util.stream.StreamSupport;
 import java.util.zip.*;
 import java.security.CodeSigner;

@@ -83,10 +84,13 @@
     // Set up JavaUtilJarAccess in SharedSecrets
     static {
         SharedSecrets.setJavaUtilJarAccess(new JavaUtilJarAccessImpl());
     }
 
+    private static final sun.misc.JavaUtilZipFileAccess zipAccess
+            = sun.misc.SharedSecrets.getJavaUtilZipFileAccess();
+
     /**
      * The JAR manifest file name.
      */
     public static final String MANIFEST_NAME = "META-INF/MANIFEST.MF";
 

@@ -187,19 +191,15 @@
 
             JarEntry manEntry = getManEntry();
 
             // If found then load the manifest
             if (manEntry != null) {
-                if (verify) {
                     byte[] b = getBytes(manEntry);
                     man = new Manifest(new ByteArrayInputStream(b));
-                    if (!jvInitialized) {
+                if (verify && !jvInitialized) {
                         jv = new JarVerifier(b);
                     }
-                } else {
-                    man = new Manifest(super.getInputStream(manEntry));
-                }
                 manRef = new SoftReference<>(man);
             }
         }
         return man;
     }

@@ -419,12 +419,17 @@
     /*
      * Reads all the bytes for a given entry. Used to process the
      * META-INF files.
      */
     private byte[] getBytes(ZipEntry ze) throws IOException {
-        try (InputStream is = super.getInputStream(ze)) {
-            return IOUtils.readFully(is, (int)ze.getSize(), true);
+        ByteBuffer bb = zipAccess.getByteBuffer(this, ze);
+        if (bb.hasArray()) {
+            return bb.array();
+        } else {
+            byte[] bytes = new byte[bb.remaining()];
+            bb.get(bytes);
+            return bytes;
         }
     }
 
     /**
      * Returns an input stream for reading the contents of the specified