Give a summary of Golang.
A system programming language developed at Google. It has inbuilt garbage collection and supports concurrency. The code can be compiled into a single executable binary and don't need addition library or runtime to execute it on server.

Can you declare a class in Golang?
Yes, Golang has a unique way of implementing class with the type interface.
See here on how to declare class in Golang

Does Go supports generic? ( trick question )
No (as of 2015)

What are the commands available in Golang to import codes from repositories such as GitHub or BitBucket?
go get and go install commands

A buffer was created with make() function and Go allocated some memory for the buffer. How do you destroy the buffer to reclaim back the memory?
buffer = nil
During runtime, buffer = nil will cause it to be garbage collected.

What are these ? (trick question)
var num int ( integer variable)
var ptr *int (a pointer)
num = 10 (assign value of 10 to variable num)
ptr = &num (pointer holding the memory address of variable num)

What are the notable differences between a slice and array ?
Array size is fixed, slice size is not. Can dynamically increase or decrease a slice's size during runtime but not for array. Slice is similar to a linked list, can do push, pop, FIFO, LIFO on slice. Use builtin append, copy functions to manipulate slice.

What's the difference between cap() and len()?
Len() - gives the number of elements inside a slice.
Cap() - gives the capacity of the slice. Number of elements the slice can accommodate.

Hash table or hash map allows fast lookup. How does Go implements hash map? (trick question)
The equivalent of hash table in Golang is map.
hash-table := make(map[string]string)

Which of the following functions, variables or identifiers that are exportable or can be invoked from another function externally and why? (trick question)