View Compilation Error

0_0_7799393_7481\Main.java:1: 需要为 class、interface 或 enum
public static void main(String[] args) throws IOException {
              ^
0_0_7799393_7481\Main.java:3: 需要为 class、interface 或 enum
        PrintWriter out = new PrintWriter(new OutputStreamWriter(System.out));
        ^
0_0_7799393_7481\Main.java:4: 需要为 class、interface 或 enum
        int a, b;
        ^
0_0_7799393_7481\Main.java:5: 需要为 class、interface 或 enum
        while(in.nextToken() != StreamTokenizer.TT_EOF)
        ^
0_0_7799393_7481\Main.java:8: 需要为 class、interface 或 enum
            in.nextToken();
            ^
0_0_7799393_7481\Main.java:9: 需要为 class、interface 或 enum
            b = (int)in.nval;
            ^
0_0_7799393_7481\Main.java:10: 需要为 class、interface 或 enum
            out.println(a + b);
            ^
0_0_7799393_7481\Main.java:11: 需要为 class、interface 或 enum
        }
        ^
0_0_7799393_7481\Main.java:13: 需要为 class、interface 或 enum
	}