// Issue 1147 https://github.com/typetools/checker-framework/issues/1147
// @below-java8-jdk-skip-test
import java.util.StringJoiner;
class Issue1147 {
public static void main(String[] args) {
StringJoiner sj = new StringJoiner(",");
sj.add("a");
sj.add(null);
System.out.println(sj);
}
}