To filter a list in groovy we can use the .find() method on list and pass the closure as filtering criteria

Sample code snippets below

.find() - To find a single value matching the critetia. Use findAll() for multiple values

def lst = ["apple", "banana", "mangos"]
lst.find { it == "apple"} // Get only apple

Output

Result: banana

findAll() - to find multiple results and filter nulls

def lstWithNulls = ["John", "Sonia", null, "David", "Andrew", null]
lstWithNulls.findAll()

Output

Result: [John, Sonia, David, Andrew]