Fix varargs warnings in libcore tests.
diff --git a/libcore/dom/src/test/java/org/w3c/domts/DOMTest.java b/libcore/dom/src/test/java/org/w3c/domts/DOMTest.java
index b39ea67..7dd8f26 100644
--- a/libcore/dom/src/test/java/org/w3c/domts/DOMTest.java
+++ b/libcore/dom/src/test/java/org/w3c/domts/DOMTest.java
@@ -165,8 +165,8 @@
           //
           //   if available use JDK 1.4's File.toURI().toString()
           //
-          Method method = File.class.getMethod("toURI", null);
-          Object uri = method.invoke(tempFile, null);
+          Method method = File.class.getMethod("toURI", (Class<?>) null);
+          Object uri = method.invoke(tempFile, (Class<?>) null);
           return uri.toString();
         }
         catch (NoSuchMethodException ex) {
diff --git a/libcore/dom/src/test/java/org/w3c/domts/LSDocumentBuilderFactory.java b/libcore/dom/src/test/java/org/w3c/domts/LSDocumentBuilderFactory.java
index 7ed0f54..b769602 100644
--- a/libcore/dom/src/test/java/org/w3c/domts/LSDocumentBuilderFactory.java
+++ b/libcore/dom/src/test/java/org/w3c/domts/LSDocumentBuilderFactory.java
@@ -272,8 +272,8 @@
     try {
       Class domImplRegistryClass = Class.forName(
           "org.w3c.dom.bootstrap.DOMImplementationRegistry");
-      Method newInstanceMethod = domImplRegistryClass.getMethod("newInstance", null);
-      Object domRegistry = newInstanceMethod.invoke(null, null);
+      Method newInstanceMethod = domImplRegistryClass.getMethod("newInstance", (Class<?>) null);
+      Object domRegistry = newInstanceMethod.invoke(null, (Class<?>) null);
       Method getDOMImplementationMethod = domImplRegistryClass.getMethod(
           "getDOMImplementation", new Class[] {String.class});
       impl = (DOMImplementation) getDOMImplementationMethod.invoke(domRegistry,
diff --git a/libcore/luni/src/test/java/java/util/FormatterTest.java b/libcore/luni/src/test/java/java/util/FormatterTest.java
index 11d82fb..1722e67 100644
--- a/libcore/luni/src/test/java/java/util/FormatterTest.java
+++ b/libcore/luni/src/test/java/java/util/FormatterTest.java
@@ -37,8 +37,8 @@
     public void test_formatNull() throws Exception {
         // We fast-path %s and %d (with no configuration) but need to make sure we handle the
         // special case of the null argument...
-        assertEquals("null", String.format(Locale.US, "%s", null));
-        assertEquals("null", String.format(Locale.US, "%d", null));
+        assertEquals("null", String.format(Locale.US, "%s", (String) null));
+        assertEquals("null", String.format(Locale.US, "%d", (Integer) null));
         // ...without screwing up conversions that don't take an argument.
         assertEquals("%", String.format(Locale.US, "%%"));
     }