diff --git a/src/windows/native/sun/windows/awt_DataTransferer.cpp b/src/windows/native/sun/windows/awt_DataTransferer.cpp
index 77a87b2028dbcda309b0f76a027daa5a5ea3df1a..9ebc2c60eeef678efbebdbae537e7529439aa533 100644
--- a/src/windows/native/sun/windows/awt_DataTransferer.cpp
+++ b/src/windows/native/sun/windows/awt_DataTransferer.cpp
@@ -274,6 +274,9 @@ Java_sun_awt_windows_WDataTransferer_dragQueryFile
 
         jclass str_clazz = env->FindClass("java/lang/String");
         DASSERT(str_clazz != NULL);
+        if (str_clazz == NULL) {
+           throw std::bad_alloc();
+        }
         jobjectArray filenames = env->NewObjectArray(nFilenames, str_clazz,
                                                      NULL);
         if (filenames == NULL) {
@@ -827,6 +830,7 @@ Java_sun_awt_windows_WDataTransferer_registerClipboardFormat(JNIEnv *env,
     TRY;
 
     LPCTSTR cStr = JNU_GetStringPlatformChars(env, str, NULL);
+    CHECK_NULL_RETURN(cStr, 0);
     jlong value = ::RegisterClipboardFormat(cStr);
     JNU_ReleaseStringPlatformChars(env, str, cStr);