Merge pull request #38702 from quaff

* pr/38702:
  Use idiomatic AssertJ assertions

Closes gh-38702

spring-boot-project/spring-boot-tools/spring-boot-loader/src/test/java/org/springframework/boot/loader/jar/StringSequenceTests.java

@@ -92,12 +92,12 @@ class StringSequenceTests {
 
 	@Test
 	void isEmptyWhenEmptyShouldReturnTrue() {
-		assertThat(new StringSequence("").isEmpty()).isTrue();
+		assertThat(new StringSequence("")).isEmpty();
 	}
 
 	@Test
 	void isEmptyWhenNotEmptyShouldReturnFalse() {
-		assertThat(new StringSequence("x").isEmpty()).isFalse();
+		assertThat(new StringSequence("x")).isNotEmpty();
 	}
 
 	@Test