View Compilation Error

0_0_30129436_2156\Main.java:1: 错误: 需要class, interface或enum
private static int calculate(int n) {
               ^
0_0_30129436_2156\Main.java:4: 错误: 需要class, interface或enum
        return 2 * calculate(n - 1);
        ^
0_0_30129436_2156\Main.java:5: 错误: 需要class, interface或enum
    }
    ^
3 个错误