Monday, March 16, 2015

UnknownServiceException

java.net.UnknownServiceException

UnknownServiceException is described in the javadoc comments as:

Thrown to indicate that an unknown service exception has occurred. Either the MIME type returned by a URL connection does not make sense, or the application is attempting to write to a read-only URL connection.
author: unascribed version: 1.14, 12/19/03 since: JDK1.0

Where is this exception thrown?

Following, is a list of exception messages cross-referenced to the source code responsible for throwing them. Click on the method link to view the code and see how the exception is thrown.

How is this exception thrown?

The following sub-sections identify where this exception is thrown, and how (or why) the code is throwing the exception.

Any source code quoted in this section is subject to the Java Research License unless stated otherwise.

java.net.URLConnection.getContentHandler()

/**
     * Gets the Content Handler appropriate for this connection.
     * @param connection the connection to use.
     */
synchronized ContentHandler getContentHandler() throws UnknownServiceException {
    String contentType = stripOffParameters(getContentType());
    ContentHandler handler = null;
    if (contentType == null) throw new UnknownServiceException('no content-type');
    try {
        handler = (ContentHandler) handlers.get(contentType);
        if (handler != null) return handler;
    } catch (Exception e) {
    }
    if (factory != null) handler = factory.createContentHandler(contentType);
    if (handler == null) {
        try {
            handler = lookupContentHandlerClassFor(contentType);
        } catch (Exception e) {
            e.printStackTrace();
            handler = UnknownContentHandlerP;
        }
        handlers.put(contentType, handler);
    }
    return handler;
}

Source: "Java SE Downloads: Java SE 6 JDK Source Code", at: http://www.oracle.com/technetwork/java/javase/downloads/index.html

java.net.URLConnection.getInputStream()

/**
     * Returns an input stream that reads from this open connection.
     * A SocketTimeoutException can be thrown when reading from the
     * returned input stream if the read timeout expires before data
     * is available for read.
     * @return     an input stream that reads from this open connection.
     * @exception  IOException              if an I/O error occurs while
     *               creating the input stream.
     * @exception  UnknownServiceException  if the protocol does not support
     *               input.
     * @see #setReadTimeout(int)
     * @see #getReadTimeout()
     */
public InputStream getInputStream() throws IOException {
    throw new UnknownServiceException('protocol doesn't support input');
}

Source: "Java SE Downloads: Java SE 6 JDK Source Code", at: http://www.oracle.com/technetwork/java/javase/downloads/index.html

java.net.URLConnection.getOutputStream()

/**
     * Returns an output stream that writes to this connection.
     * @return     an output stream that writes to this connection.
     * @exception  IOException              if an I/O error occurs while
     *               creating the output stream.
     * @exception  UnknownServiceException  if the protocol does not support
     *               output.
     */
public OutputStream getOutputStream() throws IOException {
    throw new UnknownServiceException('protocol doesn't support output');
}

Source: "Java SE Downloads: Java SE 6 JDK Source Code", at: http://www.oracle.com/technetwork/java/javase/downloads/index.html

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