code: public static boolean isSafe(Expression expression) {
          if (expression instanceof MethodCallExpression) {
              return ((MethodCallExpression) expression).isSafe();
          }
          if (expression instanceof PropertyExpression) {
              return ((PropertyExpression) expression).isSafe();
          }
          return false;
      }
docs: Tells you if the expression is a null safe dereference.
  @param expression
  expression
  @return
  true if is null safe dereference.