Do not copy data twice in swInterfaceDump()

Instead of performing getting the elements, memcpy()ing them and the
releasing, use GetByteArrayRegion().

Change-Id: I20ef181df214ac4fdcaff5a64b89ef4f879078f8
Signed-off-by: Robert Varga <nite@hq.sk>
diff --git a/vpp-japi/japi/vppjni.c b/vpp-japi/japi/vppjni.c
index b874af8..f7047bb 100644
--- a/vpp-japi/japi/vppjni.c
+++ b/vpp-japi/japi/vppjni.c
@@ -624,8 +624,7 @@
 
     vppjni_lock (jm, 7);
     my_context_id = vppjni_get_context_id (jm);
-    jbyte * name_filterP = (*env)->GetByteArrayElements (env, name_filter, NULL);
-    int cnt = (*env)->GetArrayLength (env, name_filter);
+    jsize cnt = (*env)->GetArrayLength (env, name_filter);
 
     M(SW_INTERFACE_DUMP, sw_interface_dump);
     mp->context = clib_host_to_net_u32 (my_context_id);
@@ -634,8 +633,7 @@
     if (cnt > sizeof(mp->name_filter))
         cnt = sizeof(mp->name_filter);
 
-    memcpy ((char *) mp->name_filter, name_filterP, cnt);
-    (*env)->ReleaseByteArrayElements (env, name_filter, name_filterP, 0);
+    (*env)->GetByteArrayRegion(env, name_filter, 0, cnt, (jbyte *)mp->name_filter);
 
     DEBUG_LOG ("interface filter (%d, %s, len: %d)", mp->name_filter_valid, (char *)mp->name_filter, cnt);