Java Installation and Security
Java, along with Flash and Adobe Reader, has been known to make Windows insecure for some time. Mac and Linux users now share that vulnerability.
Do You NEED Java?
Java is necessary only for certain features of LibreOffice, Apache OpenOffice and perhaps to allow other software to run on your computer.
If installed, I recommend disabling the Java plugin in your web browser — enabling it ONLY for trusted sites. Firefox disables unsafe plugins automatically.
Update Java Regularly
Update Java whenever updates are available. These releases fix security flaws in Java.
Avoid Third-party Software
Prevent Java Updater from installing third-party software.
- Open the Java Control Panel: Start ⇒ Control Panel ⇒ Java. If you see categories in the Control Panel, look for Java in Programs.
- Click on the Advanced tab.
- Scroll down to the Miscellaneous section at the bottom and place a check mark in “Suppress sponsor offers when installing or updating Java.”
If you uninstall Java, this setting will be removed, but as long as you de-select any optional software when downloading new Java versions and check during installation you shouldn't see third-party software installed on your system.
Uninstall Older Versions
I recommend uninstalling all previous versions of Java when updating. Old and unsupported versions of Java are a serious security risk and can leave your system vulnerable.
Removing older versions of Java from your system ensures that Java applications will run with the most up-to-date security and performance improvements on your system. —Oracle
Java Updater May Not Remove Older Versions
Java's updater may not automatically remove all older versions, leaving your system vulnerable.
Oracle provides instructions for uninstalling out-of-date Java versions.
I recommend that you manually verify that older versions have been removed from your system.
Uninstall Option During Update
During installation of a new version, you should see the option to uninstall older versions:
You need to provide Java permissions to check for these and to enable Java (see Firefox & Java Security).
Uninstall Java then Updating
To secure your computer I recommend that you manually uninstall all current versions, cleaning out any remaining Java-related AppData entries then install the most recent version available so you're running only the most recent version.
Manually Checking for Older Versions
Alternatively, you need to check to see if option to uninstall older versions has removed all older versions.
In either case, I recommend cleaning up the Java folders in AppData.
Cleaning Up AppData Java Folders
You need to be careful when following the instructions in this section. You can seriously harm your Windows installation if critical files are removed.
Like most Windows programs, Java keeps data in AppData (in folders labelled Oracle and Sun).
The AppData folder is normally hidden by Windows, but located in the User folder if visible (see Folder Options in Control Panel to show hidden files, folders and drives):
After running Java's Uninstall Older Versions options, I still found an obsolete Java version in the Sun AppData folder:
The Java folders are located in LocalLow under AppData. Be sure you've either uninstalled Java (all versions) or have run the option to uninstall outdated versions before proceeding.
- Navigate to the Java folders by opening the AppData then LocalLow folders.
- Look for the Oracle and Sun folders and delete the appropriate folder(s):
- If you've uninstalled Java completely, you can delete both the Oracle and Sun folders.
- If you've only removed outdated versions, open the Sun folder then delete any folders containing older versions that is present (the jre1.8._45 folder in the above example).
Firefox & Java Security
Beginning in Firefox version 52, support for NPAPI plugins in Firefox has ended, except for Adobe Flash. Some of the plugins that will no longer load include Java, Microsoft Silverlight and Adobe Acrobat. — Mozilla Support
Java Blocked in Legacy Versions
Firefox disables the Java plugin on computers running Windows with Firefox 17 or later running Java 7 Update 11 or earlier (the dark grey box on the right). Java warns you before allowing the vulnerability to be exploited.
You'll likely see a warning similar to the light grey one shown on the right for Java 7 Update 13 or later.
- Be sure to allow Java to run ONLY on sites you trust. Java can be exploited to infect your computer.
- I recommend not telling Java to remember the setting. The site may become dangerous in the future and the reminder that Java can be unsafe helps to keep you vigilant.
How to use Java if it's been blocked (e.g. for Pogo.com).
Update to the Most Recent Version
Download the latest version of Java for your operating system:
- Oracle's Consumer Java Site.
- Get the latest Java version automatically.
- The Java Downloads for All Operating Systems page has offline installers for various installations.
- You can test your Java installation.
- The Java Verification page.
Most users only need the 32-bit version of Java. If you use a 64-bit version you'll need to maintain and update both versions.
Java for Linux
- How to install Java for Linux.
- See Java Downloads for All Operating Systems for offline installers for Linux.
Java for Mac
Installing Java on the Mac has changed with newer version (Oracle's Java version 7u25 and below have been disabled by Apple in OS X).
- Java 8 requires an Intel-based Mac running Mac OS X 10.7.3 (Lion) or later and administrator privileges for installation.
- Apple supplied their own version of Java for Java versions 6 and below and used the Software Update feature on the Apple menu to check for the most current Java available for your Mac.
- Apple's Get Java for your Mac now directs you to the Oracle site.
- See Oracle's Java Downloads for All Operating Systems for offline installers for the Mac and the Mac download FAQ.
64-bit browsers have the potential for much faster browsing on 64-bit systems.
However, most addons and plugins are only available for 32-bit browsers so both 32-bit (x86) and 64-bit (x64) computers currently depend upon 32-bit browsers.
If you do install the 64-bit version of Java you'll need to ensure that you update both the 32- and 64-bit versions.
Updated: March 20, 2017