I am trying to install minecraft forge 1.12.2-14.23.0.2552 on a Mac Mojave with java "java version "14" 2020-03-17". However, upon running
java -jar forge-1.12.2-14.23.0.2552-installer.jar
to install the client I see the following terminal output:
...
Checking "/Users/me/Library/Application Support/minecraft/libraries/com/typesafe/akka/akka-actor_2.11/2.3.3/akka-actor_2.11-2.3.3.jar" internal checksums
checksums.sha1 was not found, validation failed
Downloading library com.typesafe.akka:akka-actor_2.11:2.3.3
Unpacking packed file akka-actor_2.11-2.3.3.jar.pack.xz
Signed
Checksum Length: 140942
Total Length: 2606968
Temp File: /var/folders/0g/wwq2q6nn35n8vmrwhw5qfk601zlkw_/T/art9850699590461548829.pack
Exception in thread "main" 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:165)
at net.minecraftforge.installer.SimpleInstaller.main(SimpleInstaller.java:51)
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)
... 7 more
How can I fix this problem?
