This example will show how to filter a list of objects by field in a class using groovy. The set is a class Currency and we will initialize a collection creating three elements. Next calling the findAll() method we will pass a closure that filter the list by checking if the amount is greater than 1.03. The result is 2 elements. The second snippet will demonstrate how to reduce the list and only return even numbers. A related example of show how to filter elements in a list using java 8.