minor refactor: remove URL constructor deprecation warnings (cont'd)

Author: paulk-asert

src/main/java/groovy/lang/GroovyClassLoader.java

@@ -218,7 +218,8 @@ public Class defineClass(final String name, final byte[] bytes) throws ClassForm
     public Class defineClass(final ClassNode classNode, final String file, final String newCodeBase) {
         CodeSource codeSource = null;
         try {
-            codeSource = new CodeSource(new URI("file", "", newCodeBase, null).toURL(), (java.security.cert.Certificate[]) null);
+            String path = newCodeBase.startsWith("/") ? newCodeBase : "/" + newCodeBase;
+            codeSource = new CodeSource(new URI("file", "", path, null).toURL(), (java.security.cert.Certificate[]) null);
         } catch (MalformedURLException | URISyntaxException ignore) {
         }
 

src/main/java/groovy/lang/GroovyCodeSource.java

@@ -232,7 +232,8 @@ private static CodeSource createCodeSource(final String codeBase) {
             sm.checkPermission(new GroovyCodeSourcePermission(codeBase));
         }
         try {
-            return new CodeSource(new URI("file", "", codeBase, null).toURL(), (java.security.cert.Certificate[]) null);
+            String path = codeBase.startsWith("/") ? codeBase : "/" + codeBase;
+            return new CodeSource(new URI("file", "", path, null).toURL(), (java.security.cert.Certificate[]) null);
         }
         catch (MalformedURLException | URISyntaxException e) {
             throw new RuntimeException("A CodeSource file URL cannot be constructed from the supplied codeBase: " + codeBase);