Cache jclass/jmethodID/jfieldID references

This patch introduces an initialization framework, which tracks required
references to Java classes and methods.

It works by declaring classes and their constructor signatures, which
are linked into a singly-linked list when the .so initializers are run.
Once JNI_OnLoad() is invoked, this list is walked and all classes and
their initializers are resolved. These are then used while the library
remains loaded. Once JNI_OnUnload() is called, global references are
released, so we can cleanly unload.

The class declaration results in static utility objects being emitted in
the scope of the declaration, hence to allocate an object or an array of
objects is done via simple calls.

Change-Id: I41984c13756339364dbcbf0144b947627e8e4fe1
Signed-off-by: Robert Varga <nite@hq.sk>

5 files changed, 282 insertions, 246 deletions

diff --git a/vpp-japi/Makefile.am b/vpp-japi/Makefile.am
index 5640dd1a..f1eb37da 100644
--- a/vpp-japi/Makefile.am
+++ b/vpp-japi/Makefile.am
@@ -27,7 +27,7 @@ nobase_include_HEADERS =		\
 
 lib_LTLIBRARIES += libvppjni.la
 
-libvppjni_la_SOURCES = japi/vppjni.c japi/vppapi.c
+libvppjni_la_SOURCES = japi/vppjni.c japi/vppapi.c japi/vppjni_env.h japi/vppjni_env.c
 libvppjni_la_LIBADD = -lvlibmemoryclient -lvlibapi -lsvm -lvppinfra \
 	              -lpthread -lm -lrt
 libvppjni_la_LDFLAGS = -module
diff --git a/vpp-japi/japi/vppjni.c b/vpp-japi/japi/vppjni.c
index 6e4d6ee5..b874af89 100644
--- a/vpp-japi/japi/vppjni.c
+++ b/vpp-japi/japi/vppjni.c
@@ -21,6 +21,7 @@
 #include <jni.h>
 #include <japi/vppjni.h>
 #include <japi/vppjni_bridge_domain.h>
+#include <japi/vppjni_env.h>
 #include <japi/org_openvpp_vppjapi_vppConn.h>
 #include <japi/org_openvpp_vppjapi_vppApi.h>
 
@@ -58,6 +59,29 @@ static int connect_to_vpe(char *name);
 void __stack_chk_guard (void) __attribute__((weak));
 void __stack_chk_guard (void) {  }
 
+BIND_JAPI_CLASS(vppBridgeDomainDetails, "()V");
+BIND_JAPI_BOOL_FIELD(vppBridgeDomainDetails, arpTerm);
+BIND_JAPI_BOOL_FIELD(vppBridgeDomainDetails, flood);
+BIND_JAPI_BOOL_FIELD(vppBridgeDomainDetails, forward);
+BIND_JAPI_BOOL_FIELD(vppBridgeDomainDetails, learn);
+BIND_JAPI_BOOL_FIELD(vppBridgeDomainDetails, uuFlood);
+BIND_JAPI_INT_FIELD(vppBridgeDomainDetails, bdId);
+BIND_JAPI_STRING_FIELD(vppBridgeDomainDetails, name);
+BIND_JAPI_STRING_FIELD(vppBridgeDomainDetails, bviInterfaceName);
+BIND_JAPI_OBJ_FIELD(vppBridgeDomainDetails, interfaces, "[Lorg/openvpp/vppjapi/vppBridgeDomainInterfaceDetails;");
+
+BIND_JAPI_CLASS(vppBridgeDomainInterfaceDetails, "()V");
+BIND_JAPI_BYTE_FIELD(vppBridgeDomainInterfaceDetails, splitHorizonGroup);
+BIND_JAPI_STRING_FIELD(vppBridgeDomainInterfaceDetails, interfaceName);
+
+BIND_JAPI_CLASS(vppInterfaceCounters, "(JJJJJJJJJJJJJJJJJJJJJJ)V");
+BIND_JAPI_CLASS(vppInterfaceDetails, "(ILjava/lang/String;I[BBBBBIBBIIBBBBIIII)V");
+BIND_JAPI_CLASS(vppIPv4Address, "(IB)V");
+BIND_JAPI_CLASS(vppIPv6Address, "([BB)V");
+BIND_JAPI_CLASS(vppL2Fib, "([BZLjava/lang/String;ZZ)V");
+BIND_JAPI_CLASS(vppVersion, "(Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)V");
+BIND_JAPI_CLASS(vppVxlanTunnelDetails, "(IIIII)V");
+
 void vl_client_add_api_signatures (vl_api_memclnt_create_t *mp) 
 {
     /* 
@@ -144,19 +168,6 @@ JNIEXPORT jobject JNICALL Java_org_openvpp_vppjapi_vppConn_getVppVersion
   (JNIEnv *env, jobject obj)
 {
   vppjni_main_t * jm = &vppjni_main;
-  jmethodID constr;
-  // TODO: cache this
-  jclass cls = (*env)->FindClass(env, "org/openvpp/vppjapi/vppVersion");
-  if ((*env)->ExceptionCheck(env)) {
-      (*env)->ExceptionDescribe(env);
-      return NULL;
-  }
-
-  constr = (*env)->GetMethodID(env, cls, "<init>", "(Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)V");
-  if ((*env)->ExceptionCheck(env)) {
-      (*env)->ExceptionDescribe(env);
-      return NULL;
-  }
 
   vppjni_lock (jm, 11);
   jstring progName = (*env)->NewStringUTF(env, (char *)jm->program_name);
@@ -165,7 +176,7 @@ JNIEXPORT jobject JNICALL Java_org_openvpp_vppjapi_vppConn_getVppVersion
   jstring buildDate = (*env)->NewStringUTF(env, (char *)jm->build_date);
   vppjni_unlock (jm);
 
-  return (*env)->NewObject(env, cls, constr, progName, buildDir, version, buildDate);
+  return vppVersionObject(env, progName, buildDir, version, buildDate);
 }
 
 static int jm_show_version (vppjni_main_t *jm)
@@ -527,22 +538,8 @@ JNIEXPORT jobject JNICALL Java_org_openvpp_vppjapi_vppConn_getInterfaceCounters
     vppjni_main_t * jm = &vppjni_main;
     sw_interface_stats_t *s;
     u32 sw_if_index = swIfIndex;
-    jmethodID constr;
     jobject result = NULL;
 
-    // TODO: cache this
-    jclass cls = (*env)->FindClass(env, "org/openvpp/vppjapi/vppInterfaceCounters");
-    if ((*env)->ExceptionCheck(env)) {
-        (*env)->ExceptionDescribe(env);
-        return NULL;
-    }
-
-    constr = (*env)->GetMethodID(env, cls, "<init>", "(JJJJJJJJJJJJJJJJJJJJJJ)V");
-    if ((*env)->ExceptionCheck(env)) {
-        (*env)->ExceptionDescribe(env);
-        return NULL;
-    }
-
     vppjni_lock (jm, 16);
 
     if (sw_if_index >= vec_len(jm->sw_if_stats_by_sw_if_index)) {
@@ -553,7 +550,7 @@ JNIEXPORT jobject JNICALL Java_org_openvpp_vppjapi_vppConn_getInterfaceCounters
         goto out;
     }
 
-    result = (*env)->NewObject(env, cls, constr,
+    result = vppInterfaceCountersObject(env,
             s->rx.octets, s->rx.pkts.ip4, s->rx.pkts.ip6, s->rx.pkts.unicast,
             s->rx.pkts.multicast, s->rx.pkts.broadcast, s->rx.pkts.discard,
             s->rx.pkts.fifo_full, s->rx.pkts.error, s->rx.pkts.unknown_proto,
@@ -669,9 +666,8 @@ static jobjectArray sw_if_dump_get_interfaces (JNIEnv * env)
     u32 i;
 
     int len = vec_len(jm->sw_if_dump_if_indices);
-    jmethodID jmtdIfDetails = jm->jmtdIfDetails;
 
-    jobjectArray ifArray = (*env)->NewObjectArray(env, len, jm->jcls, NULL);
+    jobjectArray ifArray = vppInterfaceDetailsArray(env, len);
 
     for (i = 0; i < len; i++) {
         u32 sw_if_index = jm->sw_if_dump_if_indices[i];
@@ -708,7 +704,7 @@ static jobjectArray sw_if_dump_get_interfaces (JNIEnv * env)
         jbyte subOuterVlanIdAny = sw_if_details->sub_outer_vlan_id_any;
         jbyte subInnerVlanIdAny = sw_if_details->sub_inner_vlan_id_any;
 
-        jobject ifObj = (*env)->NewObject(env, jm->jcls, jmtdIfDetails,
+        jobject ifObj = vppInterfaceDetailsObject(env,
                 ifIndex, ifname,
                 supIfIndex, physAddr, adminUpDown, linkUpDown,
                 linkDuplex, linkSpeed, subId, subDot1ad,
@@ -1062,20 +1058,7 @@ JNIEXPORT jobject JNICALL Java_org_openvpp_vppjapi_vppConn_getBridgeDomainDetail
 
     /* setting BridgeDomainDetails */
 
-    jclass bddClass = (*env)->FindClass(env, "org/openvpp/vppjapi/vppBridgeDomainDetails");
-    if ((*env)->ExceptionCheck(env)) {
-        (*env)->ExceptionDescribe(env);
-        rv = NULL;
-        goto out;
-    }
-
-    jmethodID midInit = (*env)->GetMethodID(env, bddClass, "<init>", "()V");
-    if ((*env)->ExceptionCheck(env)) {
-        (*env)->ExceptionDescribe(env);
-        rv = NULL;
-        goto out;
-    }
-    jobject bddObj = (*env)->NewObject(env, bddClass, midInit);
+    jobject bddObj = vppBridgeDomainDetailsObject(env);
 
     u8 *vec_bd_name = vjbd_oper_name_from_id(bdm, bd_id);
     if (NULL == vec_bd_name) {
@@ -1090,66 +1073,14 @@ JNIEXPORT jobject JNICALL Java_org_openvpp_vppjapi_vppConn_getBridgeDomainDetail
         rv = NULL;
         goto out;
     }
-    jfieldID fidName = (*env)->GetFieldID(env, bddClass, "name", "Ljava/lang/String;");
-    if ((*env)->ExceptionCheck(env)) {
-        (*env)->ExceptionDescribe(env);
-        rv = NULL;
-        goto out;
-    }
-    (*env)->SetObjectField(env, bddObj, fidName, bdName);
 
-    jfieldID fidBdId = (*env)->GetFieldID(env, bddClass, "bdId", "I");
-    if ((*env)->ExceptionCheck(env)) {
-        (*env)->ExceptionDescribe(env);
-        rv = NULL;
-        goto out;
-    }
-    (*env)->SetIntField(env, bddObj, fidBdId, bdId);
-
-    jboolean flood = bd_oper->flood;
-    jfieldID fidFlood = (*env)->GetFieldID(env, bddClass, "flood", "Z");
-    if ((*env)->ExceptionCheck(env)) {
-        (*env)->ExceptionDescribe(env);
-        rv = NULL;
-        goto out;
-    }
-    (*env)->SetBooleanField(env, bddObj, fidFlood, flood);
-
-    jboolean uuFlood = bd_oper->uu_flood;
-    jfieldID fidUuFlood = (*env)->GetFieldID(env, bddClass, "uuFlood", "Z");
-    if ((*env)->ExceptionCheck(env)) {
-        (*env)->ExceptionDescribe(env);
-        rv = NULL;
-        goto out;
-    }
-    (*env)->SetBooleanField(env, bddObj, fidUuFlood, uuFlood);
-
-    jboolean forward = bd_oper->forward;
-    jfieldID fidForward = (*env)->GetFieldID(env, bddClass, "forward", "Z");
-    if ((*env)->ExceptionCheck(env)) {
-        (*env)->ExceptionDescribe(env);
-        rv = NULL;
-        goto out;
-    }
-    (*env)->SetBooleanField(env, bddObj, fidForward, forward);
-
-    jboolean learn = bd_oper->learn;
-    jfieldID fidLearn = (*env)->GetFieldID(env, bddClass, "learn", "Z");
-    if ((*env)->ExceptionCheck(env)) {
-        (*env)->ExceptionDescribe(env);
-        rv = NULL;
-        goto out;
-    }
-    (*env)->SetBooleanField(env, bddObj, fidLearn, learn);
-
-    jboolean arpTerm = bd_oper->arp_term;
-    jfieldID fidArpTerm = (*env)->GetFieldID(env, bddClass, "arpTerm", "Z");
-    if ((*env)->ExceptionCheck(env)) {
-        (*env)->ExceptionDescribe(env);
-        rv = NULL;
-        goto out;
-    }
-    (*env)->SetBooleanField(env, bddObj, fidArpTerm, arpTerm);
+    set_vppBridgeDomainDetails_name(env, bddObj, bdName);
+    set_vppBridgeDomainDetails_bdId(env, bddObj, bdId);
+    set_vppBridgeDomainDetails_flood(env, bddObj, (jboolean)bd_oper->flood);
+    set_vppBridgeDomainDetails_uuFlood(env, bddObj, (jboolean)bd_oper->uu_flood);
+    set_vppBridgeDomainDetails_forward(env, bddObj, (jboolean)bd_oper->forward);
+    set_vppBridgeDomainDetails_learn(env, bddObj, (jboolean)bd_oper->learn);
+    set_vppBridgeDomainDetails_arpTerm(env, bddObj, (jboolean)bd_oper->arp_term);
 
     jstring bviInterfaceName = NULL;
     if (~0 != bd_oper->bvi_sw_if_index) {
@@ -1165,54 +1096,21 @@ JNIEXPORT jobject JNICALL Java_org_openvpp_vppjapi_vppConn_getBridgeDomainDetail
             goto out;
         }
     }
-    jfieldID fidBviInterfaceName = (*env)->GetFieldID(env, bddClass, "bviInterfaceName", "Ljava/lang/String;");
-    if ((*env)->ExceptionCheck(env)) {
-        (*env)->ExceptionDescribe(env);
-        rv = NULL;
-        goto out;
-    }
-    (*env)->SetObjectField(env, bddObj, fidBviInterfaceName, bviInterfaceName);
 
+    set_vppBridgeDomainDetails_bviInterfaceName(env, bddObj, bviInterfaceName);
 
     /* setting BridgeDomainInterfaceDetails */
 
-    jclass bdidClass = (*env)->FindClass(env, "org/openvpp/vppjapi/vppBridgeDomainInterfaceDetails");
-    if ((*env)->ExceptionCheck(env)) {
-        (*env)->ExceptionDescribe(env);
-        rv = NULL;
-        goto out;
-    }
-
-    jfieldID fidInterfaceName = (*env)->GetFieldID(env, bdidClass, "interfaceName", "Ljava/lang/String;");
-    if ((*env)->ExceptionCheck(env)) {
-        (*env)->ExceptionDescribe(env);
-        rv = NULL;
-        goto out;
-    }
-
-    jfieldID fidSHG = (*env)->GetFieldID(env, bdidClass, "splitHorizonGroup", "B");
-    if ((*env)->ExceptionCheck(env)) {
-        (*env)->ExceptionDescribe(env);
-        rv = NULL;
-        goto out;
-    }
-
     u32 len = vec_len(bd_oper->bd_sw_if_oper);
     ASSERT(len == bd_oper->n_sw_ifs);
 
-    jobjectArray bdidArray = (*env)->NewObjectArray(env, len, bdidClass, NULL);
+    jobjectArray bdidArray = vppBridgeDomainInterfaceDetailsArray(env, len);
 
     u32 i;
     for (i = 0; i < len; i++) {
         bd_sw_if_oper_t *sw_if_oper = &bd_oper->bd_sw_if_oper[i];
 
-        jmethodID midBdidInit = (*env)->GetMethodID(env, bdidClass, "<init>", "()V");
-        if ((*env)->ExceptionCheck(env)) {
-            (*env)->ExceptionDescribe(env);
-            rv = NULL;
-            goto out;
-        }
-        jobject bdidObj = (*env)->NewObject(env, bdidClass, midBdidInit);
+        jobject bdidObj = vppBridgeDomainInterfaceDetailsObject(env);
         (*env)->SetObjectArrayElement(env, bdidArray, i, bdidObj);
 
         u32 sw_if_index = sw_if_oper->sw_if_index;
@@ -1226,20 +1124,12 @@ JNIEXPORT jobject JNICALL Java_org_openvpp_vppjapi_vppConn_getBridgeDomainDetail
             rv = NULL;
             goto out;
         }
-        (*env)->SetObjectField(env, bdidObj, fidInterfaceName, interfaceName);
 
-        jbyte shg = sw_if_oper->shg;
-        (*env)->SetByteField(env, bdidObj, fidSHG, shg);
+        set_vppBridgeDomainInterfaceDetails_interfaceName(env, bdidObj, interfaceName);
+        set_vppBridgeDomainInterfaceDetails_splitHorizonGroup(env, bdidObj, (jbyte)sw_if_oper->shg);
     }
 
-    jfieldID fidInterfaces = (*env)->GetFieldID(env, bddClass, "interfaces",
-            "[Lorg/openvpp/vppjapi/vppBridgeDomainInterfaceDetails;");
-    if ((*env)->ExceptionCheck(env)) {
-        (*env)->ExceptionDescribe(env);
-        rv = NULL;
-        goto out;
-    }
-    (*env)->SetObjectField(env, bddObj, fidInterfaces, bdidArray);
+    set_vppBridgeDomainDetails_interfaces(env, bddObj, bdidArray);
 
     rv = bddObj;
 
@@ -1252,18 +1142,6 @@ out:
 
 static jobject l2_fib_create_object(JNIEnv *env, bd_l2fib_oper_t *l2_fib)
 {
-    jclass l2FibClass = (*env)->FindClass(env, "org/openvpp/vppjapi/vppL2Fib");
-    if ((*env)->ExceptionCheck(env)) {
-        (*env)->ExceptionDescribe(env);
-        return NULL;
-    }
-
-    jmethodID midL2FIbInit = (*env)->GetMethodID(env, l2FibClass, "<init>", "([BZLjava/lang/String;ZZ)V");
-    if ((*env)->ExceptionCheck(env)) {
-        (*env)->ExceptionDescribe(env);
-        return NULL;
-    }
-
     u32 sw_if_index = l2_fib->sw_if_index;
     const char *str_if_name = interface_name_from_sw_if_index(sw_if_index);
     if (NULL == str_if_name) {
@@ -1282,11 +1160,7 @@ static jobject l2_fib_create_object(JNIEnv *env, bd_l2fib_oper_t *l2_fib)
     jboolean filter = l2_fib->filter;
     jboolean bridgedVirtualInterface = l2_fib->bvi;
 
-    jobject l2FibObj = (*env)->NewObject(env, l2FibClass, midL2FIbInit,
-            physAddr, staticConfig, outgoingInterface, filter,
-            bridgedVirtualInterface);
-
-    return l2FibObj;
+    return vppL2FibObject(env, physAddr, staticConfig, outgoingInterface, filter, bridgedVirtualInterface);
 }
 
 JNIEXPORT jobjectArray JNICALL Java_org_openvpp_vppjapi_vppConn_l2FibTableDump
@@ -1335,14 +1209,7 @@ JNIEXPORT jobjectArray JNICALL Java_org_openvpp_vppjapi_vppConn_l2FibTableDump
   u32 count = vec_len(bd_oper->l2fib_oper);
   bd_l2fib_oper_t *l2fib_oper = bd_oper->l2fib_oper;
 
-  jclass l2FibClass = (*env)->FindClass(env, "org/openvpp/vppjapi/vppL2Fib");
-  if ((*env)->ExceptionCheck(env)) {
-      (*env)->ExceptionDescribe(env);
-      goto done;
-  }
-
-  l2FibArray = (*env)->NewObjectArray(env, count, l2FibClass, NULL);
-
+  l2FibArray = vppL2FibArray(env, count);
   for (i = 0; i < count; i++) {
       bd_l2fib_oper_t *l2_fib = &l2fib_oper[i];
       jobject l2FibObj = l2_fib_create_object(env, l2_fib);
@@ -1462,19 +1329,7 @@ JNIEXPORT jobjectArray JNICALL Java_org_openvpp_vppjapi_vppConn_ipv4AddressDump
     u32 count = vec_len(jm->ipv4_addresses);
     ipv4_address_t *ipv4_address = jm->ipv4_addresses;
 
-    jclass IPv4AddressClass = (*env)->FindClass(env, "org/openvpp/vppjapi/vppIPv4Address");
-    if ((*env)->ExceptionCheck(env)) {
-        (*env)->ExceptionDescribe(env);
-        goto done;
-    }
-
-    jmethodID midIPv4AddressInit = (*env)->GetMethodID(env, IPv4AddressClass, "<init>", "(IB)V");
-    if ((*env)->ExceptionCheck(env)) {
-        (*env)->ExceptionDescribe(env);
-        goto done;
-    }
-
-    jobjectArray ipv4AddressArray = (*env)->NewObjectArray(env, count, IPv4AddressClass, NULL);
+    jobjectArray ipv4AddressArray = vppIPv4AddressArray(env, count);
 
     for (i = 0; i < count; i++) {
         ipv4_address_t *address = &ipv4_address[i];
@@ -1482,8 +1337,7 @@ JNIEXPORT jobjectArray JNICALL Java_org_openvpp_vppjapi_vppConn_ipv4AddressDump
         jint ip = address->ip;
         jbyte prefixLength = address->prefix_length;
 
-        jobject ipv4AddressObj = (*env)->NewObject(env, IPv4AddressClass, midIPv4AddressInit,
-                ip, prefixLength);
+        jobject ipv4AddressObj = vppIPv4AddressObject(env, ip, prefixLength);
 
         (*env)->SetObjectArrayElement(env, ipv4AddressArray, i, ipv4AddressObj);
     }
@@ -1513,19 +1367,7 @@ JNIEXPORT jobjectArray JNICALL Java_org_openvpp_vppjapi_vppConn_ipv6AddressDump
     u32 count = vec_len(jm->ipv6_addresses);
     ipv6_address_t *ipv6_address = jm->ipv6_addresses;
 
-    jclass IPv6AddressClass = (*env)->FindClass(env, "org/openvpp/vppjapi/vppIPv6Address");
-    if ((*env)->ExceptionCheck(env)) {
-        (*env)->ExceptionDescribe(env);
-        goto done;
-    }
-
-    jmethodID midIPv6AddressInit = (*env)->GetMethodID(env, IPv6AddressClass, "<init>", "([BB)V");
-    if ((*env)->ExceptionCheck(env)) {
-        (*env)->ExceptionDescribe(env);
-        goto done;
-    }
-
-    jobjectArray ipv6AddressArray = (*env)->NewObjectArray(env, count, IPv6AddressClass, NULL);
+    jobjectArray ipv6AddressArray = vppIPv6AddressArray(env, count);
 
     for (i = 0; i < count; i++) {
         ipv6_address_t *address = &ipv6_address[i];
@@ -1536,8 +1378,7 @@ JNIEXPORT jobjectArray JNICALL Java_org_openvpp_vppjapi_vppConn_ipv6AddressDump
 
         jbyte prefixLength = address->prefix_length;
 
-        jobject ipv6AddressObj = (*env)->NewObject(env, IPv6AddressClass, midIPv6AddressInit,
-                ip, prefixLength);
+        jobject ipv6AddressObj = vppIPv6AddressObject(env, ip, prefixLength);
 
         (*env)->SetObjectArrayElement(env, ipv6AddressArray, i, ipv6AddressObj);
     }
@@ -1603,22 +1444,7 @@ JNIEXPORT jobjectArray JNICALL Java_org_openvpp_vppjapi_vppConn_vxlanTunnelDump
 
     u32 count = vec_len(jm->vxlan_tunnel_details);
 
-    jclass VxlanTunnelDetailsClass = (*env)->FindClass(env,
-            "org/openvpp/vppjapi/vppVxlanTunnelDetails");
-    if ((*env)->ExceptionCheck(env)) {
-        (*env)->ExceptionDescribe(env);
-        goto done;
-    }
-
-    jmethodID midVxlanTunnelDetailsInit = (*env)->GetMethodID(env,
-            VxlanTunnelDetailsClass, "<init>", "(IIIII)V");
-    if ((*env)->ExceptionCheck(env)) {
-        (*env)->ExceptionDescribe(env);
-        goto done;
-    }
-
-    jobjectArray vxlanTunnelDetailsArray = (*env)->NewObjectArray(env, count,
-            VxlanTunnelDetailsClass, NULL);
+    jobjectArray vxlanTunnelDetailsArray = vppVxlanTunnelDetailsArray(env, count);
 
     for (i = 0; i < count; i++) {
         vxlan_tunnel_details_t *details = &jm->vxlan_tunnel_details[i];
@@ -1629,8 +1455,7 @@ JNIEXPORT jobjectArray JNICALL Java_org_openvpp_vppjapi_vppConn_vxlanTunnelDump
         jint vni = details->vni;
         jint decap_next_index = details->decap_next_index;
 
-        jobject vxlanTunnelDetailsObj = (*env)->NewObject(env,
-                VxlanTunnelDetailsClass, midVxlanTunnelDetailsInit,
+        jobject vxlanTunnelDetailsObj = vppVxlanTunnelDetailsObject(env,
                 src_address, dst_address, encap_vrf_id, vni, decap_next_index);
 
         (*env)->SetObjectArrayElement(env, vxlanTunnelDetailsArray, i,
@@ -1932,23 +1757,10 @@ jint JNI_OnLoad(JavaVM *vm, void *reserved) {
     return JNI_ERR;
   }
 
-  jclass cls = (*env)->FindClass(env, "org/openvpp/vppjapi/vppInterfaceDetails");
-  if ((*env)->ExceptionCheck(env)) {
-      (*env)->ExceptionDescribe(env);
-      return JNI_ERR;
-  }
-
-  jm->jmtdIfDetails = 
-      (*env)->GetMethodID(env, cls, "<init>", "(ILjava/lang/String;I[BBBBBIBBIIBBBBIIII)V");
-  if ((*env)->ExceptionCheck(env)) {
-      (*env)->ExceptionDescribe(env);
+  if (vppjni_init(env) != 0) {
       return JNI_ERR;
   }
 
-  // methods are not local references they stay forever
-  // jclass is local reference let's hold global ref to it
-  jm->jcls = (*env)->NewGlobalRef(env, cls);
-
   jm->jvm = vm;
   return JNI_VERSION_1_6;
 }
@@ -1960,10 +1772,7 @@ void JNI_OnUnload(JavaVM *vm, void *reserved) {
     return;
   }
 
-  if (jm->jcls != NULL) {
-    (*env)->DeleteGlobalRef(env, jm->jcls);
-    jm->jcls = NULL;
-  }
+  vppjni_uninit(env);
 
   jm->jenv = NULL;
   jm->jvm = NULL;
diff --git a/vpp-japi/japi/vppjni.h b/vpp-japi/japi/vppjni.h
index 2fe2893b..847bbe92 100644
--- a/vpp-japi/japi/vppjni.h
+++ b/vpp-japi/japi/vppjni.h
@@ -150,8 +150,6 @@ typedef struct {
   /* attachment of rx thread to java thread */
   JNIEnv *jenv;
   JavaVM *jvm;
-  jclass jcls;
-  jmethodID jmtdIfDetails;  // interfaceDetails method
   uword *callback_hash;     // map context_id => jobject
   uword *ping_hash;         // map ping context_id => msg type called
 
diff --git a/vpp-japi/japi/vppjni_env.c b/vpp-japi/japi/vppjni_env.c
new file mode 100644
index 00000000..84991eee
--- /dev/null
+++ b/vpp-japi/japi/vppjni_env.c
@@ -0,0 +1,111 @@
+/*
+ * Copyright (c) 2016 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include <jni.h>
+
+#include "vppjni_env.h"
+
+// Head of the class registration list.
+static vppjni_class_t *class_head;
+// Head of the class registration list.
+static vppjni_field_t *field_head;
+
+void vppjni_init_register_class(vppjni_class_t *ptr)
+{
+    vppjni_class_t **where = &class_head;
+    while (*where != NULL) {
+        where = &((*where)->next);
+    }
+    *where = ptr;
+}
+
+void vppjni_register_field(vppjni_field_t *ptr) {
+    vppjni_field_t **where = &field_head;
+    while (*where != NULL) {
+        where = &((*where)->next);
+    }
+    *where = ptr;
+}
+
+jobject vppjni_init_new_object(JNIEnv *env, const vppjni_class_t *ptr, va_list ap) {
+    jobject obj = (*env)->NewObjectV(env, ptr->jclass, ptr->jinit, ap);
+    if ((*env)->ExceptionCheck(env)) {
+        (*env)->ExceptionDescribe(env);
+        return NULL;
+    }
+
+    return obj;
+}
+
+int vppjni_env_init(JNIEnv *env)
+{
+    vppjni_class_t *cwlk;
+    vppjni_field_t *fwlk;
+
+    for (cwlk = class_head; cwlk != NULL; cwlk = cwlk->next) {
+        jclass cls;
+        jmethodID method;
+
+        cls = (*env)->FindClass(env, cwlk->fqcn);
+        if ((*env)->ExceptionCheck(env)) {
+            (*env)->ExceptionDescribe(env);
+            vppjni_uninit(env);
+            return JNI_ERR;
+        }
+
+        method = (*env)->GetMethodID(env, cls, "<init>", cwlk->init_sig);
+        if ((*env)->ExceptionCheck(env)) {
+            (*env)->ExceptionDescribe(env);
+            vppjni_uninit(env);
+            return JNI_ERR;
+        }
+
+        cwlk->jclass = (*env)->NewGlobalRef(env, cls);
+        if (cwlk->jclass == NULL) {
+            vppjni_uninit(env);
+            return JNI_ERR;
+        }
+        cwlk->jinit = method;
+    }
+
+    for (fwlk = field_head; fwlk != NULL; fwlk = fwlk->next) {
+        fwlk->jfield = (*env)->GetFieldID(env, fwlk->clsref->jclass, fwlk->name, fwlk->type);
+        if ((*env)->ExceptionCheck(env)) {
+            (*env)->ExceptionDescribe(env);
+            vppjni_uninit(env);
+            return JNI_ERR;
+        }
+    }
+
+    return 0;
+}
+
+void vppjni_env_uninit(JNIEnv *env) {
+    vppjni_class_t *cwlk;
+    vppjni_field_t *fwlk;
+
+    for (fwlk = field_head; fwlk != NULL; fwlk = fwlk->next) {
+        fwlk->jfield = NULL;
+    }
+
+    for (cwlk = class_head; cwlk != NULL; cwlk = cwlk->next) {
+        if (cwlk->jclass != NULL ) {
+            (*env)->DeleteGlobalRef(env, cwlk->jclass);
+        }
+
+        cwlk->jclass = NULL;
+        cwlk->jinit = NULL;
+    }
+}
+
diff --git a/vpp-japi/japi/vppjni_env.h b/vpp-japi/japi/vppjni_env.h
new file mode 100644
index 00000000..fe9767b0
--- /dev/null
+++ b/vpp-japi/japi/vppjni_env.h
@@ -0,0 +1,118 @@
+/*
+ * Copyright (c) 2016 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * Utilities for accessing Java classes/method/fields in an efficient
+ * manner.
+ */
+
+/*
+ * A potentially-uninitialized reference to a Java class
+ */
+typedef struct vppjni_class {
+    // Fully-Qualified Class Name
+    const char          *fqcn;
+    // Constructor signature
+    const char          *init_sig;
+    // Global reference to class handle
+    jclass              jclass;
+    // Constructor method handle
+    jmethodID           jinit;
+    // Next item in linked list
+    struct vppjni_class *next;
+} vppjni_class_t;
+
+typedef struct jenv_field {
+    // Field name
+    const char           *name;
+    // Field type
+    const char           *type;
+    // Defining class reference
+    const vppjni_class_t *clsref;
+    // Field handle
+    jfieldID             jfield;
+    // Next item in linked list
+    struct jenv_field    *next;
+} vppjni_field_t;
+
+#define VPPJNI_CLASS_SYMBOL(name) vppjni_class_##name
+#define VPPJNI_CLASS_INIT(name) vppjni_class_##name##_init
+#define BIND_JAPI_CLASS(name, sig) \
+    static vppjni_class_t VPPJNI_CLASS_SYMBOL(name); \
+    static void VPPJNI_CLASS_INIT(name)(void) __attribute__((__constructor__)); \
+    static void VPPJNI_CLASS_INIT(name)() \
+    { \
+        VPPJNI_CLASS_SYMBOL(name).fqcn = "org/openvpp/vppjapi/" #name; \
+        VPPJNI_CLASS_SYMBOL(name).init_sig = sig; \
+        vppjni_register_class(&VPPJNI_CLASS_SYMBOL(name)); \
+    } \
+    static __attribute__((unused)) jobject name##Array(JNIEnv *env, jsize length) \
+    { \
+        return (*env)->NewObjectArray(env, length, VPPJNI_CLASS_SYMBOL(name).jclass, NULL); \
+    } \
+    static jobject name##Object(JNIEnv *env, ...) \
+    { \
+        va_list ap; \
+        va_start(ap, env); \
+        jobject obj = vppjni_new_object(env, &VPPJNI_CLASS_SYMBOL(name), ap); \
+        va_end(ap); \
+        return obj; \
+    }
+
+#define VPPJNI_FIELD_SYMBOL(cls, name) vppjni_field_##cls##_##name
+#define VPPJNI_FIELD_INIT(cls, name) vppjni_field_##cls##_##name##_init
+#define BIND_JAPI_FIELD(cls, field, sig) \
+    static vppjni_field_t VPPJNI_FIELD_SYMBOL(cls, field); \
+        static void VPPJNI_FIELD_INIT(cls, field)(void) __attribute__((__constructor__)); \
+    static void VPPJNI_FIELD_INIT(cls, field)() \
+    { \
+        VPPJNI_FIELD_SYMBOL(cls, field).name = #field; \
+        VPPJNI_FIELD_SYMBOL(cls, field).type = sig; \
+        VPPJNI_FIELD_SYMBOL(cls, field).clsref = &VPPJNI_CLASS_SYMBOL(cls); \
+        vppjni_register_field(&VPPJNI_FIELD_SYMBOL(cls, field)); \
+    }
+#define BIND_JAPI_BOOL_FIELD(cls, field) \
+    BIND_JAPI_FIELD(cls, field, "Z"); \
+    static void set_##cls##_##field(JNIEnv *env, jobject obj, jboolean value) \
+    { \
+        (*env)->SetBooleanField(env, obj, VPPJNI_FIELD_SYMBOL(cls, field).jfield, value); \
+    }
+#define BIND_JAPI_BYTE_FIELD(cls, field) \
+    BIND_JAPI_FIELD(cls, field, "B"); \
+    static void set_##cls##_##field(JNIEnv *env, jobject obj, jbyte value) \
+    { \
+        (*env)->SetByteField(env, obj, VPPJNI_FIELD_SYMBOL(cls, field).jfield, value); \
+    }
+#define BIND_JAPI_INT_FIELD(cls, field) \
+    BIND_JAPI_FIELD(cls, field, "I"); \
+    static void set_##cls##_##field(JNIEnv *env, jobject obj, jint value) \
+    { \
+        (*env)->SetIntField(env, obj, VPPJNI_FIELD_SYMBOL(cls, field).jfield, value); \
+    }
+#define BIND_JAPI_OBJ_FIELD(cls, field, sig) \
+    BIND_JAPI_FIELD(cls, field, sig); \
+    static void set_##cls##_##field(JNIEnv *env, jobject obj, jobject value) \
+    { \
+        (*env)->SetObjectField(env, obj, VPPJNI_FIELD_SYMBOL(cls, field).jfield, value); \
+    }
+#define BIND_JAPI_STRING_FIELD(cls, field) \
+    BIND_JAPI_OBJ_FIELD(cls, field, "Ljava/lang/String;")
+
+jobject vppjni_new_object(JNIEnv *env, const vppjni_class_t *ptr, va_list ap);
+void vppjni_register_class(vppjni_class_t *ptr);
+void vppjni_register_field(vppjni_field_t *ptr);
+int vppjni_init(JNIEnv *env);
+void vppjni_uninit(JNIEnv *env);
+