protocol handler : Java Glossary


protocol handler
In URL (Uniform Resource Locator) s, you see officially supported protocols like http: https: file: ftp: jdbc: and rmi:. These describe the rules by which data are extracted over such links. It is possible to define your own protocols, e.g. to extract stock ticker information or to handle encryption or compression. To do that you implement a custom class and a URLConnection.

You then name your new URLStreamHandler class com.mydomain.protocol.xxxx.Handler where xxxx is the name of your new protocol.

Then you must hook them into the official list of supported protocols so that new URL will recognise your new protocol rather than throwing a MalformedURLException. You do this by adding your implementing package name prefix e.g. com.mydomain.protocol to the java.protocol.handler.pkgs system property, e.g.

You don’t hook your protocol name itself in anywhere. Java finds it via the package/class naming convention.

Normally there is no such java.protocol.handler.pkgs property because there are no custom protocols. If you have more than one package prefix, use | to separate the names, not commas.

Learning More

Oracle’s Javadoc on URLStreamHandler class : available:

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