@SuppressWarnings

Examples

An unchecked cast to List<String> produces a warning:

List<String> names(Object data) {
    return (List<String>) data;
}
 
void main() {
    IO.println(names(List.of("Anna", "Oleg")));
}

Output:

Main.java:2: warning: [unchecked] unchecked cast
    return (List<String>) data;
                          ^
  required: List<String>
  found:    Object
1 warning
[Anna, Oleg]

With the annotation on the method there is no warning:

@SuppressWarnings("unchecked")
List<String> names(Object data) {
    return (List<String>) data;
}
 
void main() {
    IO.println(names(List.of("Anna", "Oleg")));
}

Output:

[Anna, Oleg]

Notes

Put the annotation as close to the problem as possible — on a variable or method, not on the whole class — and only when you are sure the code is safe. Several values are passed as an array: @SuppressWarnings({"unchecked", "rawtypes"}). The set of supported names depends on the compiler and IDE; javac understands the same ones as the -Xlint option.