XMLBEANS-612: Adjust classloading for better Android support

Using Classloader.getResource() for .class-files fails on Android where
the special classloader does not return class-files as resources.

As this is only done as pre-check here if loading the class will work, 
we can replace it with catching a ClassNotFoundException instead to 
only use proper reflection functionality and thus make this 
work on Android as well.

git-svn-id: https://svn.apache.org/repos/asf/xmlbeans/trunk@1901904 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/src/main/java/org/apache/xmlbeans/impl/schema/SchemaTypeLoaderImpl.java b/src/main/java/org/apache/xmlbeans/impl/schema/SchemaTypeLoaderImpl.java
index 68b1581..f59e922 100644
--- a/src/main/java/org/apache/xmlbeans/impl/schema/SchemaTypeLoaderImpl.java
+++ b/src/main/java/org/apache/xmlbeans/impl/schema/SchemaTypeLoaderImpl.java
@@ -152,14 +152,13 @@
         for (String prefix : basePackage) {
             for (String holder : baseSchemas) {
                 String clName = prefix + ".system." + holder + ".TypeSystemHolder";
-                if (cl.getResource(clName.replace(".", "/") + ".class") == null) {
-                    // if the first class isn't found in the package, continue with the next package
-                    break;
-                }
                 try {
                     @SuppressWarnings("unchecked")
                     Class<? extends SchemaTypeLoader> cls = (Class<? extends SchemaTypeLoader>) Class.forName(clName, true, cl);
                     list.add((SchemaTypeLoader) cls.getDeclaredField("typeSystem").get(null));
+                } catch (ClassNotFoundException e) {
+                    // if this class isn't found in the package, continue with the next package
+                    // this can happen and thus is ignored here
                 } catch (Exception e) {
                     throw new XmlRuntimeException(e);
                 }