Everytime I run anything sdkmanager I keep on getting this error and i am completely unsure on what to do:
Warning: Could not create settings java.lang.IllegalArgumentException
   at
com.android.sdklib.tool.sdkmanager.SdkManagerCliSettings.<init>(SdkManagerCliSettings.java:428)
   at
com.android.sdklib.tool.sdkmanager.SdkManagerCliSettings.createSettings(SdkManagerCliSettings.java:152)
   at
com.android.sdklib.tool.sdkmanager.SdkManagerCliSettings.createSettings(SdkManagerCliSettings.java:134)
   at
com.android.sdklib.tool.sdkmanager.SdkManagerCli.main(SdkManagerCli.java:57)
   at
com.android.sdklib.tool.sdkmanager.SdkManagerCli.main(SdkManagerCli.java:48)
Usage:   sdkmanager [--uninstall] [<common args>]
[--package_file=<file>] [<packages>...]   sdkmanager --update [<common
args>]   sdkmanager --list [<common args>]   sdkmanager --licenses
[<common args>]   sdkmanager --version
With --install (optional), installs or updates packages.
By default, the listed packages are installed or (if already installed)
updated to the latest version. With --uninstall, uninstall the listed packages.
<package> is a sdk-style path (e.g. "build-tools;23.0.0" or "platforms;android-23").
<package-file> is a text file where each line is a sdk-style path of a package to install or uninstall.
Multiple --package_file arguments may be specified in combination with explicit paths.
With --update, all installed packages are updated to the latest version.
With --list, all installed and available packages are printed out.
With --licenses, show and offer the option to accept licenses for all available packages that have not already been accepted.
With --version, prints the current version of sdkmanager.
Common Arguments:
    --sdk_root=<sdkRootPath>: Use the specified SDK root instead of the SDK containing this tool
    --channel=<channelId>: Include packages in channels up to <channelId>.
                           Common channels are:
                           0 (Stable), 1 (Beta), 2 (Dev), and 3 (Canary).
    --include_obsolete: With --list, show obsolete packages in the
                        package listing. With --update, update obsolete
                        packages as well as non-obsolete.
    --no_https: Force all connections to use http rather than https.
    --proxy=<http | socks>: Connect via a proxy of the given type.
    --proxy_host=<IP or DNS address>: IP or DNS address of the proxy to use.
    --proxy_port=<port #>: Proxy port to connect to.
    --verbose: Enable verbose output.
* If the env var REPO_OS_OVERRIDE is set to "windows",   "macosx", or "linux", packages will be downloaded for that OS.
I have set the sdk as a path variable and I am running Java 8. If you have any insight whatsoever please let me know.
 
    