code: public void setVersion(int major, int minor) {
          if (major > 65535 || minor > 65535) {
              throw new IllegalArgumentException("Version number element cannot exceed 65535");
          }
  
          mVersion = (minor << 16) | (major & 0xffff);
  
          String target;
          switch (major) {
          default:
              target = null;
              break;
          case 45:
              target = minor == 3 ? "1.0" : null;
              break;
          case 46:
              target = minor == 0 ? "1.2" : null;
              break;
          case 47:
              target = minor == 0 ? "1.3" : null;
              break;
          case 48:
              target = minor == 0 ? "1.4" : null;
              break;
          case 49:
              target = minor == 0 ? "1.5" : null;
              break;
          case 50:
              target = minor == 0 ? "1.6" : null;
              break;
          case 51:
              target = minor == 0 ? "1.7" : null;
              break;
          }
  
          mTarget = target;
      }
docs: Sets the version to use when writing the generated classfile, overriding
  the target.