Java has similar methods called isEmpty and isBlank, so I researched their differences and would like to share them.

To put it simply:

• isBlank: Returns true for half-width/full-width whitespace characters
• isEmpty: Returns false for half-width/full-width whitespace characters

System.out.println("isBlank(null):" + StringUtils.isBlank(null));
System.out.println("isBlank(\\"\\"):" + StringUtils.isBlank(""));
System.out.println("isBlank(\\" \\"):" + StringUtils.isBlank(" "));
System.out.println("isBlank(\\"　\\"):" + StringUtils.isBlank("　"));//Full-width whitespace character
System.out.println(“isEmpty(null):” + StringUtils.isEmpty(null));
System.out.println(“isEmpty(\”\”):” + StringUtils.isEmpty(""));
System.out.println(“isEmpty(\” \”):” + StringUtils.isEmpty(” ”));
System.out.println(“isEmpty(\”　\”):” + StringUtils.isEmpty(”　”));//Full-width whitespace character

Execution results

isBlank(null):true
isBlank(""):true
isBlank(" "):true
isBlank("　"):true

isEmpty(null):true
isEmpty(""):true
isEmpty(" "):false
isEmpty("　"):false

• Source: StringUtils.isEmpty()とStringUtils.isBlank()の違い - 前人未踏の領域へ

That’s all from the Java Gemba.