関連ワード:  create functional interface in java    creating functional interface in java 8    create custom functional interface in java    built in functional interface in java    how to create custom functional interface in java 8    can we create your own functional interface in java    can we create object of functional interface in java    how to create object for functional interface in java    which annotation is required to create a functional interface in java 8    is it possible to create a custom functional interface in java 8