What does "Safe" mean in the Collections.toArray() JavaDoc?

Question

When I read java source code, I found in the collection interface, will be safe

The returned array will be "safe" in that no references to it are Maintained by this collection.(In other words, this method must allocate a new array even if this collection is backed by an array).The caller is thus free to modify the returned array.

I do not understand the meaning, can you provide an example for me?

Answer 1

Sure:

List<String> list = Arrays.asList("foo", "bar", "baz");
String[] array = list.toArray(new String[0]);
array[0] = "qux";
System.out.println(list.get(0));  // still "foo"