stuck downloading libraries 1.12.2 forge

hello, I'm trying to download forge 1.12.2 on Mac and the download keeps getting stuck downloading libraries 

here is the installer log

checksums.sha1 was not found, validation failed
Downloading library org.scala-lang.plugins:scala-continuations-library_2.11:1.0.2
Unpacking packed file scala-continuations-library_2.11-1.0.2.jar.pack.xz
  Signed
  Checksum Length: 2416
  Total Length:    18871
  Temp File:       /var/folders/cs/3yqys74n5h32wryp8_l4mndm0000gn/T/art17025133548810071921.pack
Exception in thread "main" java.lang.reflect.InvocationTargetException
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:564)
    at net.minecraftforge.installer.Java6Gate.main(Java6Gate.java:48)
Caused by: java.lang.NoClassDefFoundError: java/util/jar/Pack200
    at net.minecraftforge.installer.DownloadUtils.unpackLibrary(DownloadUtils.java:253)
    at net.minecraftforge.installer.DownloadUtils.downloadInstalledLibraries(DownloadUtils.java:89)
    at net.minecraftforge.installer.ClientInstall.run(ClientInstall.java:131)
    at net.minecraftforge.installer.InstallerAction.run(InstallerAction.java:43)
    at net.minecraftforge.installer.InstallerPanel.run(InstallerPanel.java:406)
    at net.minecraftforge.installer.SimpleInstaller.launchGui(SimpleInstaller.java:168)
    at net.minecraftforge.installer.SimpleInstaller.main(SimpleInstaller.java:54)
    ... 5 more
Caused by: java.lang.ClassNotFoundException: java.util.jar.Pack200
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:602)
    at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522)
    ... 12 more