src/java.base/share/classes/sun/net/www/protocol/jar/JarURLConnection.java

*** 27,40 ****
--- 27,42 ----
  
  import java.io.InputStream;
  import java.io.IOException;
  import java.io.FileNotFoundException;
  import java.io.BufferedInputStream;
+ import java.io.ByteArrayInputStream;
  import java.net.URL;
  import java.net.URLConnection;
  import java.net.MalformedURLException;
  import java.net.UnknownServiceException;
+ import java.nio.ByteBuffer;
  import java.util.Enumeration;
  import java.util.Map;
  import java.util.List;
  import java.util.jar.JarEntry;
  import java.util.jar.JarFile;
*** 51,60 ****
--- 53,65 ----
  
      /* the Jar file factory. It handles both retrieval and caching.
       */
      private static final JarFileFactory factory = JarFileFactory.getInstance();
  
+     private static final sun.misc.JavaUtilZipFileAccess zipAccess
+             = sun.misc.SharedSecrets.getJavaUtilZipFileAccess();
+ 
      /* the url for the Jar file */
      private URL jarFileURL;
  
      /* the permission to get this JAR file. This is the actual, ultimate,
       * permission, returned by the jar file factory.
*** 157,167 ****
              if (jarEntry == null) {
                  throw new FileNotFoundException("JAR entry " + entryName +
                                                  " not found in " +
                                                  jarFile.getName());
              }
!             result = new JarURLInputStream (jarFile.getInputStream(jarEntry));
          }
          return result;
      }
  
      public int getContentLength() {
--- 162,181 ----
              if (jarEntry == null) {
                  throw new FileNotFoundException("JAR entry " + entryName +
                                                  " not found in " +
                                                  jarFile.getName());
              }
!             long size = jarEntry.getSize();
!             if (size > 0 && size < 512 * 1024) {
!                 byte[] bytes = new byte[(int) size];
!                 ByteBuffer bb = ByteBuffer.wrap(bytes);
!                 zipAccess.fillByteBuffer(jarFile, jarEntry, bb);
!                 result = new JarURLInputStream(new ByteArrayInputStream(bytes, 0, bb.position()));
!             } else {
!                 // Unknown or too large ZipEntry size to use a array
!                 result = new JarURLInputStream(jarFile.getInputStream(jarEntry));
!             }
          }
          return result;
      }
  
      public int getContentLength() {