What's the difference between A<:B and +B in Scala?

Question

What\'s the difference between

[A <: B]

and

[+B]

in Scala?

Answer 1

I found this blog post while researching this question. Gives an even deeper explanation of Scala variance including its theoretical basis in Category Theory

http://blogs.atlassian.com/2013/01/covariance-and-contravariance-in-scala/