Error 1618 isn't unique to Java. It is an error from Microsoft Installer (.msi) stating that another .msi is currently being processed. You see, the Microsoft Installer, msiexec.exe, can only process one installation at a time. This error will be encountered when one MSI is attempted to be installed while another is currently processing.
Please keep in mind that this doesn't necessarily mean that another Java installation is occurring. It means that msiexec.exe is currently processing another .msi installation. This could be one of thousands of other applications that use the Microsoft Installer.
Regardless, let's look at how we can overcome this when it comes to deploying Java.