FULL PRODUCT VERSION :
java version "1.8.0_66"
Java(TM) SE Runtime Environment (build 1.8.0_66-b18)
Java HotSpot(TM) 64-Bit Server VM (build 25.66-b18, mixed mode)


ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [Version 10.0.10586]

A DESCRIPTION OF THE PROBLEM :
When I create a Transformer from an invalid XSLT stylesheet, I do not expect that output is sent directly to the console. Errors should only reported through the registered ErrorListener implementation.

I ran the following example program:

import java.io.ByteArrayInputStream;
import java.io.InputStream;

import javax.xml.transform.ErrorListener;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.sax.SAXSource;

import org.xml.sax.InputSource;


public class Main implements ErrorListener
{
    static final private String INVALID_STYLESHEET = "xxx";
    static final private String SYSTEM_ID = "http://myurl.com/myDirectory/myFile.xsl";

    static public void main(String[] argv) {
        new Main().run();
    }

    void run() {
        System.out.println("This tool reveals JDK errors related to XSLT parsing");
        InputStream is = new ByteArrayInputStream(INVALID_STYLESHEET.getBytes());
        InputSource source = new InputSource(is);
        source.setSystemId(SYSTEM_ID);

        TransformerFactory factory = TransformerFactory.newInstance();
        factory.setErrorListener(this);
        try {
            factory.newTransformer(new SAXSource(source));
        }
        catch(TransformerConfigurationException e) {
            System.out.println("We catch a final TransformerConfigurationException");
        }
    }

    @Override
    public void error(TransformerException exception)
            throws TransformerException
    {
        System.out.println("Correctly handled error: " + exception.getMessage());
    }

    @Override
    public void fatalError(TransformerException exception)
            throws TransformerException
    {
        System.out.println("Correctly handled fatal: " + exception.getMessage());
    }

    @Override
    public void warning(TransformerException exception)
            throws TransformerException
    {
        System.out.println("Correctly handled warning: " + exception.getMessage());
    }
}

The output is:

This tool reveals JDK errors related to XSLT parsing
[Fatal Error] myFile.xsl:1:1: Content is not allowed in prolog.
Correctly handled error: Could not compile stylesheet
Correctly handled fatal: Content is not allowed in prolog.
We catch a final TransformerConfigurationException

The second line, which starts with "[Fatal Error]" is written by JAXP and does not come from my ErrorListener implementation. I want control over the output I show to my users and therefore this extra output is a problem for me.

One last note: I observed this problem in my own project, but I found a post on the internet (probably stackoverflow) that confirmed that this is a JDK problem. I hope the discoverer of this bug does not feel offended by me submitting it.


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Run the program listed in the description.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
This tool reveals JDK errors related to XSLT parsing
Correctly handled error: Could not compile stylesheet
Correctly handled fatal: Content is not allowed in prolog.

ACTUAL -
This tool reveals JDK errors related to XSLT parsing
[Fatal Error] myFile.xsl:1:1: Content is not allowed in prolog.
Correctly handled error: Could not compile stylesheet
Correctly handled fatal: Content is not allowed in prolog.
We catch a final TransformerConfigurationException


REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.io.ByteArrayInputStream;
import java.io.InputStream;

import javax.xml.transform.ErrorListener;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.sax.SAXSource;

import org.xml.sax.InputSource;


public class Main implements ErrorListener
{
    static final private String INVALID_STYLESHEET = "xxx";
    static final private String SYSTEM_ID = "http://myurl.com/myDirectory/myFile.xsl";

    static public void main(String[] argv) {
        new Main().run();
    }

    void run() {
        System.out.println("This tool reveals JDK errors related to XSLT parsing");
        InputStream is = new ByteArrayInputStream(INVALID_STYLESHEET.getBytes());
        InputSource source = new InputSource(is);
        source.setSystemId(SYSTEM_ID);

        TransformerFactory factory = TransformerFactory.newInstance();
        factory.setErrorListener(this);
        try {
            factory.newTransformer(new SAXSource(source));
        }
        catch(TransformerConfigurationException e) {
            System.out.println("We catch a final TransformerConfigurationException");
        }
    }

    @Override
    public void error(TransformerException exception)
            throws TransformerException
    {
        System.out.println("Correctly handled error: " + exception.getMessage());
    }

    @Override
    public void fatalError(TransformerException exception)
            throws TransformerException
    {
        System.out.println("Correctly handled fatal: " + exception.getMessage());
    }

    @Override
    public void warning(TransformerException exception)
            throws TransformerException
    {
        System.out.println("Correctly handled warning: " + exception.getMessage());
    }
}

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