ADDITIONAL SYSTEM INFORMATION :
First tested in 10.0.1. This version was then uninstalled, and a fresh Oracle JDK 10.0.2 (64-bit) was installed, but the issue remained. JDK 8u144 is also installed.

A DESCRIPTION OF THE PROBLEM :
When I specify the full path directly to either the JDK or JRE:

> "C:\Program Files\Java\jdk-10.0.2\bin\java.exe" -splash:marble24.png -jar myapplication.jar

or

> "C:\Program Files\Java\jre-10.0.2\bin\java.exe" -splash:marble24.png -jar myapplication.jar

Then the splash image, which is in the current working directory and same directory as the jar, is displayed. But when I use java via the PATH (which includes C:\Program Files (x86)\Common Files\Oracle\Java\javapath;C:\ProgramData\Oracle\Java\javapath):

> java -splash:marble24.png -jar myapplication.jar

Then the splash is not displayed. I can confirm this is the same java version 10.0.2 when run via javapath:

> java -version
java version "10.0.2" 2018-07-17
Java(TM) SE Runtime Environment 18.3 (build 10.0.2+13)
Java HotSpot(TM) 64-Bit Server VM 18.3 (build 10.0.2+13, mixed mode)

This issue has been reported previously by one user, and confirmed by a second user, but was closed as "Cannot Reproduce" in JDK-8190252. I don't have permission to modify that issue, but I have reproduced it, and I can see why it was not reproduced previously. The wrong steps were taken. Four reproduction attempts were described but they do not cover the issue:

1. java - splash:images/splash.gif misc.SplashDemo
2. C:\ProgramData\Oracle\Java\javapath\java.exe -splash:images\splash.gif misc.SplashDemo
3. "C:\Program Files\Java\jdk-9.0.1\bin\java.exe" -splash:images\splash.gif misc.SplashDemo
4. Created a jar file, as mentioned in the tutorial, and ran with the command java -jar splashDemo.jar

But the correct way to reproduce would be like this:

5. java - splash:images/splash.gif -jar application.jar

Note that this differs from (1) as it uses -jar and determines the main file from the jar's MANIFEST.MF (note however there should be no splash in the jar's manifest).

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Use javapath with the command line "java -splash:image.gif -jar jarname.jar". It is essential that the -jar option be used, i.e. use this command with only the image and jar names differing. The main file should be determined by the jar's manifest via the "Main-Class" attribute. Ensure also that the "SplashScreen-Image" attribute is *not* in the manifest.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The splash is image is displayed
ACTUAL -
No splash image is displayed

FREQUENCY : always