master
8367561: Getting some "header" property from a file:// URL causes a file descriptor leak
8345625: Better HTTP connections
8378687: Improve delegation of HttpURLConnection
8378003: JarURLConnection.getCertificates() and getCodeSigners() incorrectly return null for signed JAR files after JDK-8377338
8348986: Improve coverage of enhanced exception messages
8377070: Update jimage format to support classes compiled with preview feature enabled
8344189: Cleanup code in sun.net.www.protocol.mailto.MailToURLConnection and sun.net.smtp after JEP 486 integration