ADDITIONAL SYSTEM INFORMATION :
Any Windows OS with NTFS file system.

A DESCRIPTION OF THE PROBLEM :
NTFS has the concept of alternate data streams. https://docs.microsoft.com/en-us/archive/blogs/askcore/alternate-data-streams-in-ntfs These streams are represented as a file name with a colon. For example, you might have example.txt and an alternate stream named example.txt:stream1.

Using the old java.io APIs, it is possible to access these streams. For example, new File("example.txt:stream1").length() returns the length of the alternate stream, not the root file. However, java.nio.Paths.get("example.txt:stream1") throws an InvalidPathException. The JDK WindowsPathParser is written to reject colons in the file path: https://github.com/openjdk/jdk/blob/53b2368d495d865c8b5c4e481a57f6e06a616490/src/java.base/windows/classes/sun/nio/fs/WindowsPathParser.java#L225

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
In a CMD prompt:
echo example > example.txt
echo hello > example.txt:stream1

Then run the following Java code:

File exampleFile = new File("example.txt");
assert exampleFile.length() == 10;
File streamFile = new File("example.txt:stream1");
assert streamFile.length() == 8;

Path streamPathViaFile = streamFile.toPath();
Path streamPathViaPaths = Paths.get("example.txt:stream1");

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Both assertions pass, and the "program" runs to completion.
ACTUAL -
Both assertions pass, but the program throws InvalidPathException when streamFile.toPath() is called.

CUSTOMER SUBMITTED WORKAROUND :
I have not found a workaround using the java.nio APIs

FREQUENCY : always