Re: How to update file/folders metadata using Public Java API Services?
The public Java API is typically documented very well in the official documentation - have you checked this resource to help you get started? Specifically the NodeService - which should be the most often mentioned service in any Java-focussed documentation / blog post - is one of the key services to deal with nodes and metadata. Content is handled by the ContentService while you can simplify some navigation over files/folders using the FileFolderService, if you can live with some of its restrictions (e.g. it restricts access to content to "only" file and folder-like nodes which is great for a traditional DMS use case but annoying if you - like me - tend to operate more with a "generic" ECM mindset).