When to use the rel = canonical tag in Java?

The rel=canonical tag is a great way to go. By the way, FYI, it can be used cross-domain. So, for example, if I republish the content on A at something like a Medium.com/@RandFish, which is, I think, my Medium account, /a, guess what?
For More Information Please Refer:
https://moz.com/blog/rel-canonical
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