Получение classname'а из .class-файла

[annmuor]

Быстро, просто, без рефлекшена!

1. 
   public String getClassNameFromInputStream(InputStream is) {
2. 
   Map strings = new HashMap<>();
3. 
   Map classMap = new HashMap<>();
4. 
   String ret = null;
5. 
   try {
6. 
   DataInputStream dis = new DataInputStream(is);
7. 
   dis.skip(8);
8. 
   int pool_count = dis.readShort();
9. 
   int idx = 1;
10. 
    while (pool_count - idx > 0) {
11. 
    int type = dis.read();
12. 
    switch (type) {
13. 
    case 1:
14. 
    int len = dis.readShort();
15. 
    byte[] buf = new byte[len];
16. 
    dis.read(buf);
17. 
    strings.put(idx, new String(buf));
18. 
    break;
19. 
    case 7:
20. 
    int index = dis.readShort();
21. 
    classMap.put(idx, index);
22. 
    break;
23. 
    case 8:
24. 
    case 16:
25. 
    dis.skip(2);
26. 
    break;
27. 
    case 3:
28. 
    case 4:
29. 
    case 9:
30. 
    case 10:
31. 
    case 11:
32. 
    case 12:
33. 
    case 18:
34. 
    dis.skip(4);
35. 
    break;
36. 
    case 5:
37. 
    case 6:
38. 
    dis.skip(8);
39. 
    idx++;
40. 
    break;
41. 
    case 15:
42. 
    dis.skip(3);
43. 
    default:
44. 
    System.out.println(idx + " unknown byte " + type);
45. 
    }
46. 
    idx++;
47. 
    }
48. 
    dis.skip(2);
49. 
    int thisClass = dis.readShort();
50. 
    dis.close();
51. 
    ret = strings.get(classMap.get(thisClass)).replace('/', '.');
52. 
    } catch (IOException e) {
53. 
    }
54. 
    return ret;
55. 
    }