On Windows, Java prevents starting the Installer twice by creating (two) lock files. If those files exist, Java Installer show the Message: “Another Java installation is in progress (…)”.
If Java Installer crashes, or Windows crashes during Java Installation, the installer cannot delete the lock files when finalizing.
Deleting the lock files, unlocks the Installer and Java can be installed again.
The lock files are located at:
C:\ProgramData\Oracle\Java\JAVA_INSTALL_FLAG %USERPROFILE%\AppData\LocalLow\Sun\Java\JAVA_INSTALL_FLAG %USERPROFILE%\AppData\LocalLow\Oracle\Java\JAVA_INSTALL_FLAG