diff --git a/spring-boot-project/spring-boot-tools/spring-boot-loader/src/test/java/org/springframework/boot/loader/net/protocol/jar/JarUrlTests.java b/spring-boot-project/spring-boot-tools/spring-boot-loader/src/test/java/org/springframework/boot/loader/net/protocol/jar/JarUrlTests.java
index 082550058e6..e35db7f04f0 100644
--- a/spring-boot-project/spring-boot-tools/spring-boot-loader/src/test/java/org/springframework/boot/loader/net/protocol/jar/JarUrlTests.java
+++ b/spring-boot-project/spring-boot-tools/spring-boot-loader/src/test/java/org/springframework/boot/loader/net/protocol/jar/JarUrlTests.java
@@ -44,43 +44,43 @@ class JarUrlTests {
 	@BeforeEach
 	void setup() throws MalformedURLException {
 		this.jarFile = new File(this.temp, "my.jar");
-		this.jarFileUrlPath = this.temp.toURI().toURL().toString().substring("file:".length());
+		this.jarFileUrlPath = this.jarFile.toURI().toURL().toString().substring("file:".length()).replace("!", "%21");
 	}
 
 	@Test
 	void createWithFileReturnsUrl() {
-		URL url = JarUrl.create(this.temp);
+		URL url = JarUrl.create(this.jarFile);
 		assertThat(url).hasToString("jar:file:%s!/".formatted(this.jarFileUrlPath));
 	}
 
 	@Test
 	void createWithFileAndEntryReturnsUrl() {
 		JarEntry entry = new JarEntry("lib.jar");
-		URL url = JarUrl.create(this.temp, entry);
+		URL url = JarUrl.create(this.jarFile, entry);
 		assertThat(url).hasToString("jar:nested:%s/!lib.jar!/".formatted(this.jarFileUrlPath));
 	}
 
 	@Test
 	void createWithFileAndNullEntryReturnsUrl() {
-		URL url = JarUrl.create(this.temp, (JarEntry) null);
+		URL url = JarUrl.create(this.jarFile, (JarEntry) null);
 		assertThat(url).hasToString("jar:file:%s!/".formatted(this.jarFileUrlPath));
 	}
 
 	@Test
 	void createWithFileAndNameReturnsUrl() {
-		URL url = JarUrl.create(this.temp, "lib.jar");
+		URL url = JarUrl.create(this.jarFile, "lib.jar");
 		assertThat(url).hasToString("jar:nested:%s/!lib.jar!/".formatted(this.jarFileUrlPath));
 	}
 
 	@Test
 	void createWithFileAndNullNameReturnsUrl() {
-		URL url = JarUrl.create(this.temp, (String) null);
+		URL url = JarUrl.create(this.jarFile, (String) null);
 		assertThat(url).hasToString("jar:file:%s!/".formatted(this.jarFileUrlPath));
 	}
 
 	@Test
 	void createWithFileNameAndPathReturnsUrl() {
-		URL url = JarUrl.create(this.temp, "lib.jar", "com/example/My.class");
+		URL url = JarUrl.create(this.jarFile, "lib.jar", "com/example/My.class");
 		assertThat(url).hasToString("jar:nested:%s/!lib.jar!/com/example/My.class".formatted(this.jarFileUrlPath));
 	}