Can't install Oracle Java 9

Question

It seems that Oracle has changed their website such that all the downloads don't work for the standard Ubuntu install method.

sudo add-apt-repository ppa:webupd8team/java -y
sudo apt-get update
sudo apt-get install oracle-java9-installer

just results in:

Reading package lists... Done
Building dependency tree       
Reading state information... Done
oracle-java9-installer is already the newest version (9b181-1~webupd8~2).
0 upgraded, 0 newly installed, 0 to remove and 9 not upgraded.
2 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
Do you want to continue? [Y/n] y
Setting up oracle-java8-installer (8u144-1~webupd8~0) ...
Using wget settings from /var/cache/oracle-jdk8-installer/wgetrc
Downloading Oracle Java 8...
--2017-10-18 13:45:03--  http://download.oracle.com/otn-pub/java/jdk/8u144-b01/090f390dda5b47b9b721c7dfaa008135/jdk-8u144-linux-x64.tar.gz
Resolving download.oracle.com (download.oracle.com)... 184.150.187.72, 184.150.187.88
Connecting to download.oracle.com (download.oracle.com)|184.150.187.72|:80... connected.
HTTP request sent, awaiting response... 302 Moved Temporarily
Location: https://edelivery.oracle.com/otn-pub/java/jdk/8u144-b01/090f390dda5b47b9b721c7dfaa008135/jdk-8u144-linux-x64.tar.gz [following]
--2017-10-18 13:45:04--  https://edelivery.oracle.com/otn-pub/java/jdk/8u144-b01/090f390dda5b47b9b721c7dfaa008135/jdk-8u144-linux-x64.tar.gz
Resolving edelivery.oracle.com (edelivery.oracle.com)... 23.39.16.136, 2600:1409:a:39c::2d3e, 2600:1409:a:39e::2d3e
Connecting to edelivery.oracle.com (edelivery.oracle.com)|23.39.16.136|:443... connected.
HTTP request sent, awaiting response... 302 Moved Temporarily
Location: http://download.oracle.com/otn-pub/java/jdk/8u144-b01/090f390dda5b47b9b721c7dfaa008135/jdk-8u144-linux-x64.tar.gz?AuthParam=1508359624_127c598683c58f386f142ac265251dbe [following]
--2017-10-18 13:45:04--  http://download.oracle.com/otn-pub/java/jdk/8u144-b01/090f390dda5b47b9b721c7dfaa008135/jdk-8u144-linux-x64.tar.gz?AuthParam=1508359624_127c598683c58f386f142ac265251dbe
Connecting to download.oracle.com (download.oracle.com)|184.150.187.72|:80... connected.
HTTP request sent, awaiting response... 404 Not Found
2017-10-18 13:45:04 ERROR 404: Not Found.

download failed
Oracle JDK 8 is NOT installed.
dpkg: error processing package oracle-java8-installer (--configure):
 subprocess installed post-installation script returned error exit status 1
Setting up oracle-java9-installer (9b181-1~webupd8~2) ...
Using wget settings from /var/cache/oracle-jdk9-installer/wgetrc
Downloading Oracle Java 9...
--2017-10-18 13:45:05--  http://download.oracle.com/otn-pub/java/jdk/9+181/jdk-9_linux-x64_bin.tar.gz
Resolving download.oracle.com (download.oracle.com)... 184.150.187.88, 184.150.187.72
Connecting to download.oracle.com (download.oracle.com)|184.150.187.88|:80... connected.
HTTP request sent, awaiting response... 302 Moved Temporarily
Location: https://edelivery.oracle.com/otn-pub/java/jdk/9+181/jdk-9_linux-x64_bin.tar.gz [following]
--2017-10-18 13:45:05--  https://edelivery.oracle.com/otn-pub/java/jdk/9+181/jdk-9_linux-x64_bin.tar.gz
Resolving edelivery.oracle.com (edelivery.oracle.com)... 23.39.16.136, 2600:1409:a:39c::2d3e, 2600:1409:a:39e::2d3e
Connecting to edelivery.oracle.com (edelivery.oracle.com)|23.39.16.136|:443... connected.
HTTP request sent, awaiting response... 302 Moved Temporarily
Location: http://download.oracle.com/otn-pub/java/jdk/9+181/jdk-9_linux-x64_bin.tar.gz?AuthParam=1508359625_bdbf7e44fa803075b290d8fca35d82f8 [following]
--2017-10-18 13:45:05--  http://download.oracle.com/otn-pub/java/jdk/9+181/jdk-9_linux-x64_bin.tar.gz?AuthParam=1508359625_bdbf7e44fa803075b290d8fca35d82f8
Connecting to download.oracle.com (download.oracle.com)|184.150.187.88|:80... connected.
HTTP request sent, awaiting response... 404 Not Found
2017-10-18 13:45:06 ERROR 404: Not Found.

download failed
Oracle JDK 9 is NOT installed.
dpkg: error processing package oracle-java9-installer (--configure):
 subprocess installed post-installation script returned error exit status 1
Errors were encountered while processing:
 oracle-java8-installer
 oracle-java9-installer
E: Sub-process /usr/bin/dpkg returned an error code (1)

And when I try to go to, say, http://download.oracle.com/otn-pub/java/jdk/9+181/jdk-9_linux-x64_bin.tar.gz?AuthParam=1508359625_bdbf7e44fa803075b290d8fca35d82f8, I get the web page that looks like this:

So it appears that Oracle has gone and broken Linux installations. Or maybe there's something I can do on my end?