Don't expose URLs from InnerLoader

Update the CLI Groovy InnerLoader to not expose URLs. This prevents the
'TLD skipped' log messages from Tomcat that occurred previously due to
the InnerLoader and parent returning the same URLs.

Fixes gh-277

spring-boot-cli/src/main/java/org/springframework/boot/cli/compiler/ExtendedGroovyClassLoader.java

@@ -50,6 +50,8 @@ public class ExtendedGroovyClassLoader extends GroovyClassLoader {
 
 	private static final String SHARED_PACKAGE = "org.springframework.boot.groovy";
 
+	private static final URL[] NO_URLS = new URL[] {};
+
 	private final Map<String, byte[]> classResources = new HashMap<String, byte[]>();
 
 	private final GroovyCompilerScope scope;
@@ -127,7 +129,14 @@ public class ExtendedGroovyClassLoader extends GroovyClassLoader {
 				.doPrivileged(new PrivilegedAction<InnerLoader>() {
 					@Override
 					public InnerLoader run() {
-						return new InnerLoader(ExtendedGroovyClassLoader.this);
+						return new InnerLoader(ExtendedGroovyClassLoader.this) {
+							// Don't return URLs from the inner loader so that Tomcat only
+							// searches the parent. Fixes 'TLD skipped' issues
+							@Override
+							public URL[] getURLs() {
+								return NO_URLS;
+							}
+						};
 					}
 				});
 		return new ExtendedClassCollector(loader, unit, su);