stuck downloading libraries 1.12.2 forge

[jt100]

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