Normalize paths in JvmUtils

Fixes problem in Windoze where file paths cannot be so easily
converted to URLs.

Fixes gh-767

spring-boot-tools/spring-boot-loader-tools/src/main/java/org/springframework/boot/loader/tools/JvmUtils.java

@@ -17,6 +17,7 @@
 package org.springframework.boot.loader.tools;
 
 import java.io.File;
+import java.net.MalformedURLException;
 import java.net.URL;
 import java.net.URLClassLoader;
 
@@ -42,7 +43,7 @@ abstract class JvmUtils {
 		String javaHome = getJavaHome();
 		for (String location : TOOLS_LOCATIONS) {
 			try {
-				URL url = new URL("file://" + javaHome + "/" + location);
+				URL url = new URL(javaHome + "/" + location);
 				if (new File(url.toURI()).exists()) {
 					return url;
 				}
@@ -55,7 +56,13 @@ abstract class JvmUtils {
 	}
 
 	private static String getJavaHome() {
-		return System.getProperty("java.home");
+		try {
+			return new File(System.getProperty("java.home")).toURI().toURL()
+					.toExternalForm();
+		}
+		catch (MalformedURLException e) {
+			throw new IllegalStateException("Cannot locate java.home", e);
+		}
 	}
 
 }