Check if Tomcat and MySQL are already installed on machine

How can I check using Java if Tomcat and MySQL are already installed on machine? If it is installed I开发者_Go百科 have to disable those options in my installer.

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If Tomcat is installed as a service on Windows, you can check the registry: HKEY_LOCAL_MACHINE\SOFTWARE\Apache Software Foundation\Tomcat\[version]\InstallPath.

To read the registry from Java, you would need to use something like JNA, the methods Advapi32Util.registryGetKeys() and Advapi32Util.registryGetStringValue() can help.