diff --git a/android-metadata-generator/src/src/com/telerik/metadata/Builder.java b/android-metadata-generator/src/src/com/telerik/metadata/Builder.java
index 17fce2ca1..5620e10fc 100644
--- a/android-metadata-generator/src/src/com/telerik/metadata/Builder.java
+++ b/android-metadata-generator/src/src/com/telerik/metadata/Builder.java
@@ -60,7 +60,11 @@ public static TreeNode build(String[] paths) throws Exception {
                 // our class path API 17
                 // Class<?> clazz = Class.forName(className, false, loader);
                 ClassDescriptor clazz = ClassRepo.findClass(className);
-                generate(clazz, root);
+                if (clazz == null) {
+                    throw new ClassNotFoundException("Class " + className + " not found in the input android libraries.");
+                } else {
+                    generate(clazz, root);
+                }
             } catch (Throwable e) {
                 System.out.println("Skip " + className);
                 System.out.println("\tError: " + e.toString());
@@ -248,6 +252,12 @@ private static TreeNode getOrCreateNode(TreeNode root, TypeDescriptor type)
         } else {
             String name = ClassUtil.getCanonicalName(type.getSignature());
             ClassDescriptor clazz = ClassRepo.findClass(name);
+
+            // if clazz is not found in the ClassRepo, the method/field being analyzed will be skipped
+            if (clazz == null) {
+                return null;
+            }
+
             node = getOrCreateNode(root, clazz, null);
         }
 
diff --git a/android-metadata-generator/src/src/com/telerik/metadata/ClassRepo.java b/android-metadata-generator/src/src/com/telerik/metadata/ClassRepo.java
index 0aac04e4a..d4c98efbf 100644
--- a/android-metadata-generator/src/src/com/telerik/metadata/ClassRepo.java
+++ b/android-metadata-generator/src/src/com/telerik/metadata/ClassRepo.java
@@ -12,16 +12,6 @@ private ClassRepo() {
     private static ArrayList<ClassMapProvider> cachedProviders = new ArrayList<ClassMapProvider>();
 
     public static void addToCache(ClassMapProvider classMapProvider) {
-        for (String className : classMapProvider.getClassMap().keySet()) {
-            for (ClassMapProvider cachedProvider : cachedProviders) {
-                ClassDescriptor clazz = cachedProvider.getClassMap().get(className);
-                if (clazz != null) {
-                    String errMsg = "Class " + className + " conflict: "
-                                    + classMapProvider.getPath() + " and " + cachedProvider.getPath();
-                    throw new IllegalArgumentException(errMsg);
-                }
-            }
-        }
         cachedProviders.add(classMapProvider);
     }
 
@@ -33,6 +23,7 @@ public static ClassDescriptor findClass(String className) {
                 break;
             }
         }
+
         return clazz;
     }
 
diff --git a/android-metadata-generator/src/src/com/telerik/metadata/Generator.java b/android-metadata-generator/src/src/com/telerik/metadata/Generator.java
index eb01f016e..5eed78077 100644
--- a/android-metadata-generator/src/src/com/telerik/metadata/Generator.java
+++ b/android-metadata-generator/src/src/com/telerik/metadata/Generator.java
@@ -29,7 +29,7 @@ public static void main(String[] args) throws Exception {
                 "You need to pass an output directory!");
         }
 
-        if (args != null && args.length > 1) {
+        if (args.length > 1) {
             params = new String[args.length - 1];
             for (int i = 1; i < args.length; i++) {
                 params[i - 1] = args[i];