ArrayList<Object> list = new ArrayList<Object>();
list.add(1);
list.add("Java");
list.add(3.14);
System.out.println(list.toString());
I tried:
ArrayList<String> list2 = (String)list;
But it gave me a compile error.
Since this is actually not a list of strings, the easiest way is to loop over it and convert each item into a new list of strings yourself:
List<String> strings = list.stream()
.map(object -> Objects.toString(object, null))
.collect(Collectors.toList());
Or when you're not on Java 8 yet:
List<String> strings = new ArrayList<>(list.size());
for (Object object : list) {
strings.add(Objects.toString(object, null));
}
Or when you're not on Java 7 yet:
List<String> strings = new ArrayList<String>(list.size());
for (Object object : list) {
strings.add(object != null ? object.toString() : null);
}
Note that you should be declaring against the interface (java.util.List
in this case), not the implementation.