In Manage Jenkins / Configure System, it is no longer possible to view a pull-down list of JDK versions when "Install from java.sun.com" is selected. Instead, there is a text box into which the version must be typed.

It turns out that only values of "version" corresponding to the names of files under ~jenkins/cache/jdks/LINUX/amd64 are valid. I tried upgrading from 7u72 to 7u75 by altering the version string and this is what happened when I tried to run the build:

Installing JDK jdk-7u75-oth-JPR
java.io.IOException: JDK data is empty.
at hudson.tools.JDKInstaller.locate(JDKInstaller.java:361)
at hudson.tools.JDKInstaller.performInstallation(JDKInstaller.java:134)
at hudson.tools.InstallerTranslator.getToolHome(InstallerTranslator.java:68)
at hudson.tools.ToolLocationNodeProperty.getToolHome(ToolLocationNodeProperty.java:107)
at hudson.tools.ToolInstallation.translateFor(ToolInstallation.java:205)
at hudson.model.JDK.forNode(JDK.java:130)

PS by manually downloading the latest JDK gz file into the cache folder and renaming it to jdk-7u75-oth-JPR, the above build then works.