関連ワード:  java check if collection is null or empty    java check if set is null or empty    java 8 check if collection is null or empty    java test if string is null or empty    java test if list is null or empty    java check if is null or empty    java check if object is null or empty    java check if map is null or empty    java check if array is null or empty    java check if integer is null or empty  
結果 : java test if collection is null or empty