logback-android/src/main/java/ch/qos/logback/core/android/AndroidContextUtil.java
@TargetApi(21)
  public String getNoBackupFilesDirectoryPath() {
    return Build.VERSION.SDK_INT >= 21 &&
            this.context != null
            ? absPath(this.context.getNoBackupFilesDir())
            : "";
  }
@TargetApi(21)
  public String getNoBackupFilesDirectoryPath() {
    return Build.VERSION.SDK_INT >= 21 &&
            this.context != null
            ? absPath(this.context.getNoBackupFilesDir())
            : "";
  }
@ TargetApi ( 21 ) public String getNoBackupFilesDirectoryPath ( ) { return Build . VERSION . SDK_INT >= 21 && this . context != null ? absPath ( this . context . getNoBackupFilesDir ( ) ) : "" ; }
Returns the absolute path to the directory on the Android
filesystem similar to {@link #getFilesDirectoryPath()}.
The difference is these files are excluded from automatic
backup to remote storage by {@code android.app.backup.BackupAgent}.
This API is only available on SDK 21+. On older versions,
this function returns an empty string.

@return the absolute path to the files directory
(example: "/data/data/com.example/nobackup/files")
Returns the absolute path to the directory on the Android filesystem similar to { @link #getFilesDirectoryPath () } . The difference is these files are excluded from automatic backup to remote storage by { @code android . app . backup . BackupAgent } . This API is only available on SDK 21 + . On older versions this function returns an empty string .