A DESCRIPTION OF THE PROBLEM :
StreamResult(File) writes to incorrect file path if # is part of the file path

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
See test case below.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Write file ./output/#/dom.xml
ACTUAL -
Write file ./output

Exception in thread "main" javax.xml.transform.TransformerException: java.io.FileNotFoundException: ./output (Is a directory)
at java.xml/com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.getOutputHandler(TransformerImpl.java:540)
at java.xml/com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transform(TransformerImpl.java:354)
at test.Main.main(Main.java:26)
Caused by: java.io.FileNotFoundException: ./output (Is a directory)
at java.base/java.io.FileOutputStream.open0(Native Method)
at java.base/java.io.FileOutputStream.open(FileOutputStream.java:298)
at java.base/java.io.FileOutputStream.<init>(FileOutputStream.java:237)
at java.base/java.io.FileOutputStream.<init>(FileOutputStream.java:126)
at java.xml/com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.getOutputHandler(TransformerImpl.java:513)
... 2 more

---------- BEGIN SOURCE ----------

package test;

import java.io.File;

import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.w3c.dom.Document;

public class Main {

public static void main(String[] args) throws Exception {
File f = new File("./output/#/dom.xml");
f.getParentFile().mkdirs();

Document dom = DocumentBuilderFactory.newInstance().newDocumentBuilder().newDocument();
dom.appendChild(dom.createElement("root"));

Transformer tr = TransformerFactory.newInstance().newTransformer();
tr.setOutputProperty(OutputKeys.INDENT, "yes");
tr.transform(new DOMSource(dom), new StreamResult(f));
}

}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Use StreamResult(OutputStream) with standard FileOutputStream instead.

FREQUENCY : always