protected static <T> T checkNotNull(T object) {
    if (object == null) {
      setInvalid();
    }
    return object;
  }
Verifies that the provided object reference is null. If it is null, then this VFS is marked
as invalid for the current environment.

@param object The object reference to check for null.
src/main/java/org/apache/ibatis/io/JBoss6VFS.java