Installing 10.13.1 beta 3 apparently revs something so that a reported Java installation is now version "15.0.2":
hawkeye:~ maser$ cat /System/Library/Frameworks/JavaVM.framework/Resources/Info.plist
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-/
<plist version="1.0">
<dict>
<key>BuildMachineOSBuild</key>
<string>16B2657</string>
<key>CFBundleDevelopmentRegion</key>
<string>English</string>
<key>CFBundleExecutable</key>
<string>JavaVM</string>
<key>CFBundleIdentifier</key>
<string>com.apple.JavaVM</string>
<key>CFBundleInfoDictionaryVersion</key>
<string>6.0</string>
<key>CFBundleName</key>
<string>Java Virtual Machine</string>
<key>CFBundlePackageType</key>
<string>FMWK</string>
<key>CFBundleShortVersionString</key>
<string>15.0.2</string>
However, this version of Java doesn't work with apps that still apparently rely on this (like SPSS 24) and you can't install apple legacy Java 15.0.1 over this because 15.0.2 is "newer".
Hopefully this means that a "15.0.2" version will be showing up from Apple, but otherwise, this is a brand new issue introduced in this beta, so be aware...