Find your current Java version in the Programs and Features section of Windows and from the command line on a Mac. You only need to have Java installed on a Windows or Mac computer to begin.Continue Reading
In Windows 7, click the Start button, and select Control Panel from the pop-up menu. In Windows 8, select the desktop from the Start screen. Right-click the bottom-left corner of the screen, and select Control Panel from the menu. For Mac users, click Spotlight, and type "Terminal" in the search field. Click Terminal from the menu.
In Windows, select Programs from the Control Panel window. Next, click the Programs and Features link to open a new window.
In Windows, locate Java in the list, and check the version number for your specific Java installation. Close the window when done. For Mac users, type "/Library/Internet Plug-Ins/JavaAppletPlugin.plugin/Contents/Home/bin/java -version" without quotes in the Terminal window, and press the Enter or Return key to view the JRE version. To view the default version of the JDK, type "java -version" without quotes, and press the Enter key. Close the Terminal window when done.