関連ワード:  java check if collection is empty or null    check if collection is empty or null    java check if string is empty or null    java check if list is empty or null    java check if map is empty or null    java check if array is empty or null    java check if object is empty or null    java check if set is empty or null    java check if arraylist is empty or null    java check if empty or null  
結果 : java check if collection is empty or null