In UML, class A extends class B, I don't know if it's true but it's a dependency relationship, not inheritance.
It says A «extend» B. I tried inheritance relationship but it didn't feel right.
How to use it in code?
There seems to be a confusion on UML elements here:
In UML there is indeed an «extend» dependency relationship, but it is specific to use-cases. It has nothing to do with the java extend.
In Java there is indeed an extend
statement to specify inheritance. This is what UML calls generalization/specialization (hollow triangle arrow head/ plain line).
You therefore need to correct your diagram, using inheritance instead of dependency.