diff --git a/spring-boot-tools/spring-boot-loader/src/main/java/org/springframework/boot/loader/jar/JarURLConnection.java b/spring-boot-tools/spring-boot-loader/src/main/java/org/springframework/boot/loader/jar/JarURLConnection.java
index ce4b558dbb..dd7d88b9c1 100644
--- a/spring-boot-tools/spring-boot-loader/src/main/java/org/springframework/boot/loader/jar/JarURLConnection.java
+++ b/spring-boot-tools/spring-boot-loader/src/main/java/org/springframework/boot/loader/jar/JarURLConnection.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2014 the original author or authors.
+ * Copyright 2012-2016 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -59,6 +59,8 @@ class JarURLConnection extends java.net.JarURLConnection {
 
 	private static final JarEntryName EMPTY_JAR_ENTRY_NAME = new JarEntryName("");
 
+	private static final String FILE_COLON_DOUBLE_SLASH = "file://";
+
 	private static ThreadLocal<Boolean> useFastExceptions = new ThreadLocal<Boolean>();
 
 	private final JarFile jarFile;
@@ -73,11 +75,8 @@ class JarURLConnection extends java.net.JarURLConnection {
 		// What we pass to super is ultimately ignored
 		super(EMPTY_JAR_URL);
 		this.url = url;
-		String urlFile = url.getFile();
-		if (urlFile.startsWith("file://")) {
-			urlFile = "file:" + urlFile.substring("file://".length());
-		}
-		String spec = urlFile.substring(jarFile.getUrl().getFile().length());
+		String spec = getNormalizedFile(url)
+				.substring(jarFile.getUrl().getFile().length());
 		int separator;
 		while ((separator = spec.indexOf(SEPARATOR)) > 0) {
 			jarFile = getNestedJarFile(jarFile, spec.substring(0, separator));
@@ -87,6 +86,13 @@ class JarURLConnection extends java.net.JarURLConnection {
 		this.jarEntryName = getJarEntryName(spec);
 	}
 
+	private String getNormalizedFile(URL url) {
+		if (!url.getFile().startsWith(FILE_COLON_DOUBLE_SLASH)) {
+			return url.getFile();
+		}
+		return "file:" + url.getFile().substring(FILE_COLON_DOUBLE_SLASH.length());
+	}
+
 	private JarFile getNestedJarFile(JarFile jarFile, String name) throws IOException {
 		JarEntry jarEntry = jarFile.getJarEntry(name);
 		if (jarEntry == null) {
diff --git a/spring-boot-tools/spring-boot-loader/src/test/java/org/springframework/boot/loader/jar/JarFileTests.java b/spring-boot-tools/spring-boot-loader/src/test/java/org/springframework/boot/loader/jar/JarFileTests.java
index e58237a54d..f08243bb20 100644
--- a/spring-boot-tools/spring-boot-loader/src/test/java/org/springframework/boot/loader/jar/JarFileTests.java
+++ b/spring-boot-tools/spring-boot-loader/src/test/java/org/springframework/boot/loader/jar/JarFileTests.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2015 the original author or authors.
+ * Copyright 2012-2016 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -321,24 +321,18 @@ public class JarFileTests {
 
 	@Test
 	public void createNonNestedUrlFromString() throws Exception {
-		JarFile.registerUrlProtocolHandler();
-		String spec = "jar:" + this.rootJarFile.toURI() + "!/2.dat";
-		URL url = new URL(spec);
-		assertThat(url.toString(), equalTo(spec));
-		InputStream inputStream = url.openStream();
-		assertThat(inputStream, notNullValue());
-		assertThat(inputStream.read(), equalTo(2));
-		JarURLConnection connection = (JarURLConnection) url.openConnection();
-		assertThat(connection.getURL().toString(), equalTo(spec));
-		assertThat(connection.getJarFileURL().toURI(), equalTo(this.rootJarFile.toURI()));
-		assertThat(connection.getEntryName(), equalTo("2.dat"));
+		nonNestedJarFileFromString(
+				"jar:file:" + this.rootJarFile.getAbsolutePath() + "!/2.dat");
 	}
 
 	@Test
-	public void createNonNestedUrlFromStringCreatedUsingPath() throws Exception {
-		// gh-5287
+	public void createNonNestedUrlFromStringWithDoubleSlash() throws Exception {
+		nonNestedJarFileFromString(
+				"jar:file://" + this.rootJarFile.getAbsolutePath() + "!/2.dat");
+	}
+
+	private void nonNestedJarFileFromString(String spec) throws Exception {
 		JarFile.registerUrlProtocolHandler();
-		String spec = "jar:" + this.rootJarFile.toPath().toUri() + "!/2.dat";
 		URL url = new URL(spec);
 		assertThat(url.toString(), equalTo(spec));
 		InputStream inputStream = url.openStream();