public void setDefaultTarget(int target) {
    throwIfImmutable();

    if (target < 0) {
      throw new IllegalArgumentException("target < 0");
    }

    if (targets.size() != size) {
      throw new RuntimeException("non-default elements not all set");
    }

    targets.add(target);
  }
Sets the default target. It is only valid to call this method when all the non-default elements
have been set.

@param target {@code >= 0;} the absolute (not relative) default target address
android/android_framework/dex-maker/src/main/java/com/android/dx/cf/code/SwitchList.java