How to remove all null elements from a ArrayList or String Array?

Question

I try with a loop like that

// ArrayList tourists

for (Tourist t : tourists) {
    if (t != null) {     
        t.setId(idForm); 
    }   
}

Answer 1

Using Java 8 this can be performed in various ways using streams, parallel streams and removeIf method:

List stringList = new ArrayList<>(Arrays.asList(null, "A", "B", null, "C", null));
List listWithoutNulls1 = stringList.stream()
                .filter(Objects::nonNull)
                .collect(Collectors.toList()); //[A,B,C]
List listWithoutNulls2 = stringList.parallelStream()
                .filter(Objects::nonNull)
                .collect(Collectors.toList()); //[A,B,C]
stringList.removeIf(Objects::isNull); //[A,B,C]

The parallel stream will make use of available processors and will speed up the process for reasonable sized lists. It is always advisable to benchmark before using streams.