diff --git a/spring-boot-project/spring-boot-tools/spring-boot-loader/src/main/java/org/springframework/boot/loader/net/protocol/jar/JarUrl.java b/spring-boot-project/spring-boot-tools/spring-boot-loader/src/main/java/org/springframework/boot/loader/net/protocol/jar/JarUrl.java
index 1e40ced32f1f..ca2230d36d7b 100644
--- a/spring-boot-project/spring-boot-tools/spring-boot-loader/src/main/java/org/springframework/boot/loader/net/protocol/jar/JarUrl.java
+++ b/spring-boot-project/spring-boot-tools/spring-boot-loader/src/main/java/org/springframework/boot/loader/net/protocol/jar/JarUrl.java
@@ -79,7 +79,7 @@ public static URL create(File file, String nestedEntryName, String path) {
 	}
 
 	private static String getJarReference(File file, String nestedEntryName) {
-		String jarFilePath = file.toURI().getPath();
+		String jarFilePath = file.toURI().getRawPath().replace("!", "%21");
 		return (nestedEntryName != null) ? "nested:" + jarFilePath + "/!" + nestedEntryName : "file:" + jarFilePath;
 	}
 
diff --git a/spring-boot-project/spring-boot-tools/spring-boot-loader/src/test/java/org/springframework/boot/loader/net/protocol/jar/JarUrlConnectionTests.java b/spring-boot-project/spring-boot-tools/spring-boot-loader/src/test/java/org/springframework/boot/loader/net/protocol/jar/JarUrlConnectionTests.java
index c9553c731379..83f522553332 100644
--- a/spring-boot-project/spring-boot-tools/spring-boot-loader/src/test/java/org/springframework/boot/loader/net/protocol/jar/JarUrlConnectionTests.java
+++ b/spring-boot-project/spring-boot-tools/spring-boot-loader/src/test/java/org/springframework/boot/loader/net/protocol/jar/JarUrlConnectionTests.java
@@ -512,6 +512,20 @@ void getLastModifiedHeaderReturnsFileModifiedTime() throws IOException {
 		}
 	}
 
+	@Test
+	void getJarFileWhenInFolderWithEncodedCharsReturnsJarFile() throws Exception {
+		this.temp = new File(this.temp, "te#st");
+		this.temp.mkdirs();
+		this.file = new File(this.temp, "test.jar");
+		this.url = JarUrl.create(this.file, "nested.jar");
+		assertThat(this.url.toString()).contains("te%23st");
+		TestJar.create(this.file);
+		JarUrlConnection connection = JarUrlConnection.open(this.url);
+		JarFile jarFile = connection.getJarFile();
+		assertThat(jarFile).isNotNull();
+		assertThat(jarFile.getEntry("3.dat")).isNotNull();
+	}
+
 	private long withoutNanos(long epochMilli) {
 		return Instant.ofEpochMilli(epochMilli).with(ChronoField.NANO_OF_SECOND, 0).toEpochMilli();
 	}
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 e35db7f04f0e..7ca3fb683995 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
@@ -25,6 +25,8 @@
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
 
+import org.springframework.boot.loader.net.util.UrlDecoder;
+
 import static org.assertj.core.api.Assertions.assertThat;
 
 /**
@@ -84,4 +86,14 @@ void createWithFileNameAndPathReturnsUrl() {
 		assertThat(url).hasToString("jar:nested:%s/!lib.jar!/com/example/My.class".formatted(this.jarFileUrlPath));
 	}
 
+	@Test
+	void createWithReservedCharsInName() throws Exception {
+		String badFolderName = "foo#bar!/baz/!oof";
+		this.temp = new File(this.temp, badFolderName);
+		setup();
+		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));
+		assertThat(UrlDecoder.decode(url.toString())).contains(badFolderName);
+	}
+
 }