Java IntelliJ 13.1.4"此语言级别不支持Lambda表达式."

Question

当我尝试使用表达式时,value -> value我得到一个错误,表示不支持Lambda.我目前正在使用1.8 JDK和Lambda支持,但我仍然得到错误.我的猜测是它是IntelliJ 13.1.4,但我并不积极.

public static void grades(){
    final List<Integer> grade = new ArrayList<Integer>();
    int gradelistnumber = 1;
    int inputedgrade = 0;

    while(inputedgrade != -1){
        System.out.println("Enter Grade for student " + gradelistnumber + " (1-50): ");
        inputedgrade = sc.nextInt();
        grade.add(inputedgrade);
        gradelistnumber++;


    }

    System.out.println("Class Average: " + System.out.println(grade.stream().mapToInt(value -> value /*error*/).sum()));
  }

}

Answer 1

除了到File > Project Structure > Project > Project Language Level其他有提,
你也应该检查File > Project Structure > **Modules** > Sources > Project Language Level并设置为8

Answer 2

去

File > Project Structure > Project > Project Language Level

检查它是否是8.0