logback-android/src/main/java/ch/qos/logback/classic/Logger.java
private synchronized void handleParentLevelChange(int newParentLevelInt) {
    // changes in the parent levelInt affect children only if their levelInt is
    // null
    if (level == null) {
      effectiveLevelInt = newParentLevelInt;

      // propagate the parent levelInt change to this logger's children
      if (childrenList != null) {
        int len = childrenList.size();
        for (int i = 0; i < len; i++) {
          Logger child = (Logger) childrenList.get(i);
          child.handleParentLevelChange(newParentLevelInt);
        }
      }
    }
  }
private synchronized void handleParentLevelChange(int newParentLevelInt) {
    // changes in the parent levelInt affect children only if their levelInt is
    // null
    if (level == null) {
      effectiveLevelInt = newParentLevelInt;

      // propagate the parent levelInt change to this logger's children
      if (childrenList != null) {
        int len = childrenList.size();
        for (int i = 0; i < len; i++) {
          Logger child = (Logger) childrenList.get(i);
          child.handleParentLevelChange(newParentLevelInt);
        }
      }
    }
  }
This method is invoked by parent logger to let this logger know that the
prent's levelInt changed.

@param newParentLevelInt