---

id: 29

slug: "string-isblank"

title: "String.isBlank()"

category: "strings"

difficulty: "beginner"

jdkVersion: "11"

oldLabel: "Java 8"

modernLabel: "Java 11+"

oldApproach: "trim().isEmpty()"

modernApproach: "isBlank()"

oldCode: |-

boolean blank =

str.trim().isEmpty();

// or: str.trim().length() == 0

modernCode: |-

boolean blank = str.isBlank();

// handles Unicode whitespace too

summary: "Check for blank strings with a single method call."

explanation: "isBlank() returns true if the string is empty or contains only whitespace,\

\ including Unicode whitespace characters that trim() misses."

whyModernWins:

- icon: "📖"

title: "Self-documenting"

desc: "isBlank() says exactly what it checks."

- icon: "🌐"

title: "Unicode-aware"

desc: "Handles all Unicode whitespace, not just ASCII."

- icon: "⚡"

title: "No allocation"

desc: "No intermediate trimmed string is created."

support:

state: "available"

description: "Widely available since JDK 11 (Sept 2018)"

prev: "collections/unmodifiable-collectors"

next: "strings/string-strip"

related:

- "strings/string-formatted"

- "strings/string-strip"

- "strings/string-indent-transform"

docs:

- title: "String.isBlank()"

href: "https://docs.oracle.com/en/java/javase/25/docs/api/java.base/java/lang/String.html#isBlank()"