How to deserialize an object array into a Map using Jackson, using one of the object's properties as key?

Question

I am deserializing a Json object which contains as one of it's properties an array of objects, like so:

{
   name: 'abc',
   symbols: {
       { a: '1', b: 'test'}, { a: '2', b: 'test'}, { a: '3', b: 'test'} ... 
   ]
}

If I deserialize into a class like this, it works fine:

class MyContainer {
  private String name;
  private Symbol[] symbols;
}

However, I get many items in the symbols array, and would like to deserialize into a map instead, where the key is the a property of each symbol, and the value is the symbol object itself, as to have them indexed by that property for fast lookups later:

class MyContainer {
  private String name;
  private Map<String, Symbol> symbols;
}

I can assure the a properties in the array always have a unique value.

I saw many posts about maps but none seemed to cover this use case, which is quite common for me.

How can I accomplish this with Jackson?

Thanks!