How to check for an empty Optional array of strings in Java?

Question

How can I check for an empty Optional array of strings in Java?

In the case is empty I would like to return a message.

@PostMapping("/users")
@ResponseBody
public String saveUsers(@RequestParam Optional<String>[] paramArray) {
    System.out.println("param " + paramArray);
    String msg = "";
    int i = 0;
    if (paramArray is empty) {
        msg = "paramArray is empty";
    } else {
        for (Optional<String> paramArrayItem : paramArray) {
            msg += "param[" + i + "]" + paramArrayItem + "\n";
            i++;
        }
    }
    return msg;
}

Answer 1

Optional<String>[] is an array of Optional<String> elements.

You'd rather want to have optional array of strings, so you need to change paramArray type to Optional<String[]>.

@PostMapping("/users")
@ResponseBody
public String saveUsers(@RequestParam Optional<String[]> paramArray) {
    System.out.println("param " + paramArray);
    String msg = "";
    int i = 0;
    if (paramArray.isEmpty()) {
        msg = "paramArray is empty";
    } else {
        for (String paramArrayItem : paramArray.get()) {
            msg += "param[" + i + "]" + paramArrayItem + "\n";
            i++;
        }
    }
    return msg;
}