I got few JSON in my project and after importing them to Eclipse Neon I saw red mark on file (and on project) complaining "JSON Problem".
My question is how can I disable/skip/ignore the JSON errors from Eclipse Neon,
You can configure JSON validation and error marking under Preferences > JSON > JSON Files > Validation.
It can be configured for the entire workspace or on a per-project level (see the link on the preferences page "Configure Project Specific Settings..."