src/jdk.zipfs/share/classes/jdk/nio/zipfs/JarFileSystem.java

*** 60,79 ****
  
      JarFileSystem(ZipFileSystemProvider provider, Path zfpath, Map<String,?> env) throws IOException {
          super(provider, zfpath, env);
          if (isMultiReleaseJar()) {
              int version;
!             Object o = env.get("multi-release");
              if (o instanceof String) {
                  String s = (String)o;
                  if (s.equals("runtime")) {
                      version = Runtime.version().feature();
                  } else {
!                     version = Integer.parseInt(s);
                  }
              } else if (o instanceof Integer) {
!                 version = (Integer)o;
              } else if (o instanceof Version) {
                  version = ((Version)o).feature();
              } else {
                  throw new IllegalArgumentException("env parameter must be String, Integer, "
                          + "or Version");
--- 60,79 ----
  
      JarFileSystem(ZipFileSystemProvider provider, Path zfpath, Map<String,?> env) throws IOException {
          super(provider, zfpath, env);
          if (isMultiReleaseJar()) {
              int version;
!             Object o = getRuntimeVersion(env);
              if (o instanceof String) {
                  String s = (String)o;
                  if (s.equals("runtime")) {
                      version = Runtime.version().feature();
                  } else {
!                     version = Version.parse(s).feature();
                  }
              } else if (o instanceof Integer) {
!                 version = Version.parse(((Integer)o).toString()).feature();
              } else if (o instanceof Version) {
                  version = ((Version)o).feature();
              } else {
                  throw new IllegalArgumentException("env parameter must be String, Integer, "
                          + "or Version");
*** 81,90 ****
--- 81,102 ----
              createVersionedLinks(version < 0 ? 0 : version);
              setReadOnly();
          }
      }
  
+     /**
+      * Utility method to get the release version for a multi-release JAR.  It
+      * first checks the documented property {@code releaseVersion} and if not
+      * found checks the original property {@code multi-release}
+      * @param env  ZIP FS map
+      * @return  release version or null if it is not specified
+      */
+     private Object getRuntimeVersion(Map<String, ?> env) {
+         Object o = env.get(ZipFileSystemProvider.RELEASE_VERSION);
+         return   o != null ? o : env.get(ZipFileSystemProvider.MULTI_RELEASE);
+     }
+ 
      private boolean isMultiReleaseJar() throws IOException {
          try (InputStream is = newInputStream(getBytes("/META-INF/MANIFEST.MF"))) {
              String multiRelease = new Manifest(is).getMainAttributes()
                  .getValue(Attributes.Name.MULTI_RELEASE);
              return "true".equalsIgnoreCase(multiRelease);