diff --git a/src/main/native/jni_utils.cc b/src/main/native/jni_utils.cc
index 602e9aa..5a3441c 100644
--- a/src/main/native/jni_utils.cc
+++ b/src/main/native/jni_utils.cc
@@ -20,8 +20,9 @@ JNIEnv *getJNIEnv() {
   return pEnv;
 }
 
+// Class fully qualified names
 const char CLS_NODE[] = "org/bblfsh/client/v2/Node";
-const char CLS_CTX[] = "org/bblfsh/client/v2/Context";
+const char CLS_CTX[] = "org/bblfsh/client/v2/ContextExt";
 const char CLS_OBJ[] = "java/lang/Object";
 const char CLS_RE[] = "java/lang/RuntimeException";
 const char CLS_JNODE[] = "org/bblfsh/client/v2/JNode";
@@ -34,6 +35,7 @@ const char CLS_JUINT[] = "org/bblfsh/client/v2/JUint";
 const char CLS_JARR[] = "org/bblfsh/client/v2/JArray";
 const char CLS_JOBJ[] = "org/bblfsh/client/v2/JObject";
 
+// Method signatures
 const char METHOD_JNODE_KEY_AT[] = "(I)Ljava/lang/String;";
 const char METHOD_JNODE_VALUE_AT[] = "(I)Lorg/bblfsh/client/v2/JNode;";
 const char METHOD_JOBJ_ADD[] =
@@ -126,8 +128,8 @@ jfieldID getField(JNIEnv *env, jobject obj, const char *name) {
   return jfid;
 }
 
-static jmethodID MethodID(JNIEnv *env, const char *method,
-                          const char *signature, const char *className) {
+jmethodID MethodID(JNIEnv *env, const char *method, const char *signature,
+                   const char *className) {
   jclass cls = env->FindClass(className);
   checkJvmException(std::string("failed to find a class ").append(className));
 
@@ -171,7 +173,7 @@ jobject ObjectMethod(JNIEnv *env, const char *method, const char *signature,
   va_start(varargs, object);
   jobject res = env->CallObjectMethodV(*object, mId, varargs);
   va_end(varargs);
-  checkJvmException(std::string("failed get varargs for ")
+  checkJvmException(std::string("failed to get varargs for ")
                         .append(className)
                         .append(".")
                         .append(method));
diff --git a/src/main/native/jni_utils.h b/src/main/native/jni_utils.h
index d1801ae..3794490 100644
--- a/src/main/native/jni_utils.h
+++ b/src/main/native/jni_utils.h
@@ -44,4 +44,5 @@ jint IntMethod(JNIEnv *, const char *, const char *, const char *,
 jobject ObjectMethod(JNIEnv *, const char *, const char *, const char *,
                      const jobject *, ...);
 
+jmethodID MethodID(JNIEnv *, const char *, const char *, const char *);
 #endif
diff --git a/src/main/native/org_bblfsh_client_v2_Context.h b/src/main/native/org_bblfsh_client_v2_Context.h
index 4deed86..57bde96 100644
--- a/src/main/native/org_bblfsh_client_v2_Context.h
+++ b/src/main/native/org_bblfsh_client_v2_Context.h
@@ -10,15 +10,23 @@ extern "C" {
 /*
  * Class:     org_bblfsh_client_v2_Context
  * Method:    root
- * Signature: ()Lorg/bblfsh/client/v2/Node;
+ * Signature: ()Lorg/bblfsh/client/v2/JNode;
  */
 JNIEXPORT jobject JNICALL Java_org_bblfsh_client_v2_Context_root
   (JNIEnv *, jobject);
 
+/*
+ * Class:     org_bblfsh_client_v2_Context
+ * Method:    filter
+ * Signature: ()V
+ */
+JNIEXPORT void JNICALL Java_org_bblfsh_client_v2_Context_filter
+  (JNIEnv *, jobject);
+
 /*
  * Class:     org_bblfsh_client_v2_Context
  * Method:    encode
- * Signature: (Lorg/bblfsh/client/v2/Node;)Ljava/nio/ByteBuffer;
+ * Signature: (Lorg/bblfsh/client/v2/JNode;)Ljava/nio/ByteBuffer;
  */
 JNIEXPORT jobject JNICALL Java_org_bblfsh_client_v2_Context_encode
   (JNIEnv *, jobject, jobject);
@@ -31,14 +39,6 @@ JNIEXPORT jobject JNICALL Java_org_bblfsh_client_v2_Context_encode
 JNIEXPORT void JNICALL Java_org_bblfsh_client_v2_Context_dispose
   (JNIEnv *, jobject);
 
-/*
- * Class:     org_bblfsh_client_v2_Context
- * Method:    filter
- * Signature: ()V
- */
-JNIEXPORT void JNICALL Java_org_bblfsh_client_v2_Context_filter
-  (JNIEnv *, jobject);
-
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/main/native/org_bblfsh_client_v2_ContextExt.h b/src/main/native/org_bblfsh_client_v2_ContextExt.h
new file mode 100644
index 0000000..9287e9b
--- /dev/null
+++ b/src/main/native/org_bblfsh_client_v2_ContextExt.h
@@ -0,0 +1,45 @@
+/* DO NOT EDIT THIS FILE - it is machine generated */
+#include <jni.h>
+/* Header for class org_bblfsh_client_v2_ContextExt */
+
+#ifndef _Included_org_bblfsh_client_v2_ContextExt
+#define _Included_org_bblfsh_client_v2_ContextExt
+#ifdef __cplusplus
+extern "C" {
+#endif
+/*
+ * Class:     org_bblfsh_client_v2_ContextExt
+ * Method:    root
+ * Signature: ()Lorg/bblfsh/client/v2/Node;
+ */
+JNIEXPORT jobject JNICALL Java_org_bblfsh_client_v2_ContextExt_root
+  (JNIEnv *, jobject);
+
+/*
+ * Class:     org_bblfsh_client_v2_ContextExt
+ * Method:    filter
+ * Signature: ()V
+ */
+JNIEXPORT void JNICALL Java_org_bblfsh_client_v2_ContextExt_filter
+  (JNIEnv *, jobject);
+
+/*
+ * Class:     org_bblfsh_client_v2_ContextExt
+ * Method:    encode
+ * Signature: (Lorg/bblfsh/client/v2/Node;)Ljava/nio/ByteBuffer;
+ */
+JNIEXPORT jobject JNICALL Java_org_bblfsh_client_v2_ContextExt_encode
+  (JNIEnv *, jobject, jobject);
+
+/*
+ * Class:     org_bblfsh_client_v2_ContextExt
+ * Method:    dispose
+ * Signature: ()V
+ */
+JNIEXPORT void JNICALL Java_org_bblfsh_client_v2_ContextExt_dispose
+  (JNIEnv *, jobject);
+
+#ifdef __cplusplus
+}
+#endif
+#endif
diff --git a/src/main/native/org_bblfsh_client_v2_libuast_Libuast.cc b/src/main/native/org_bblfsh_client_v2_libuast_Libuast.cc
index 5c8d182..46f820c 100644
--- a/src/main/native/org_bblfsh_client_v2_libuast_Libuast.cc
+++ b/src/main/native/org_bblfsh_client_v2_libuast_Libuast.cc
@@ -2,6 +2,7 @@
 
 #include "jni_utils.h"
 #include "org_bblfsh_client_v2_Context.h"
+#include "org_bblfsh_client_v2_ContextExt.h"
 #include "org_bblfsh_client_v2_Context__.h"
 #include "org_bblfsh_client_v2_Node.h"
 #include "org_bblfsh_client_v2_libuast_Libuast.h"
@@ -49,6 +50,28 @@ jobject asJvmBuffer(uast::Buffer buf) {
   return env->NewDirectByteBuffer(buf.ptr, buf.size);
 }
 
+// Checks if a given object is of Node/JNode class
+bool isContext(jobject obj, JNIEnv *env) {
+  if (!obj) return false;
+
+  jclass ctxCls = env->FindClass(CLS_CTX);
+  checkJvmException("failed to find class " + std::string(CLS_CTX));
+
+  return env->IsInstanceOf(obj, ctxCls);
+}
+
+bool assertNotContext(jobject obj) {
+  JNIEnv *env = getJNIEnv();
+  if (isContext(obj, env)) {
+    auto reCls = env->FindClass(CLS_RE);
+    checkJvmException("failed to find class " + std::string(CLS_RE));
+
+    env->ThrowNew(reCls, "cannot use UAST Context as a Node");
+    return false;
+  }
+  return true;
+}
+
 // ==========================================
 // External UAST Context (managed by libuast)
 // ==========================================
@@ -72,21 +95,19 @@ class ContextExt {
 
     JNIEnv *env = getJNIEnv();
     jclass cls = env->FindClass(CLS_NODE);
-    if (env->ExceptionOccurred() || !cls) {
-      return 0;
-    }
+    checkJvmException("failed to find class " + std::string(CLS_NODE));
 
     if (!env->IsInstanceOf(obj, cls)) {
-      const char *err = "ContextExt.toHandle() called not on Node type";
+      auto err = std::string("ContextExt.toHandle() called not on")
+                     .append(CLS_NODE)
+                     .append(" type");
       ctx->SetError(err);
       return 0;
     }
 
     auto handle =
         (NodeHandle)env->GetLongField(obj, getField(env, obj, "handle"));
-    if (env->ExceptionOccurred() || !handle) {
-      return 0;
-    }
+    checkJvmException("failed to get field Node.handle");
 
     return handle;
   }
@@ -103,11 +124,12 @@ class ContextExt {
     return toJ(root);
   }
 
-  // Encode serializes external UAST.
+  // Encode serializes the external UAST.
   // Borrows the reference.
   jobject Encode(jobject node, UastFormat format) {
-    NodeHandle h = toHandle(node);
-    uast::Buffer data = ctx->Encode(h, format);
+    if (!assertNotContext(node)) return nullptr;
+
+    uast::Buffer data = ctx->Encode(toHandle(node), format);
     return asJvmBuffer(data);
   }
 };
@@ -131,7 +153,7 @@ class Node : public uast::Node<Node *> {
   static NodeKind kindOf(jobject obj) {
     JNIEnv *env = getJNIEnv();
     // TODO(bzz): expose JNode.kind & replace type comparison \w a string test
-    if (!obj) {
+    if (!obj || env->IsInstanceOf(obj, env->FindClass(CLS_JNULL))) {
       return NODE_NULL;
     } else if (env->IsInstanceOf(obj, env->FindClass(CLS_JSTR))) {
       return NODE_STRING;
@@ -189,49 +211,71 @@ class Node : public uast::Node<Node *> {
 
   NodeKind Kind() { return kind; }
 
-  // TODO(#90): implement and test (all 'As*' are unused stubs for now)
-  std::string *AsString() {
+  std::string *AsString() {  // new ref
     if (!str) {
+      const char methodName[] = "str";
       JNIEnv *env = getJNIEnv();
-      const char *utf = env->GetStringUTFChars((jstring)obj, 0);
+      jstring jstr = (jstring)ObjectMethod(
+          env, methodName, "()Ljava/lang/String;", CLS_JSTR, &obj);
+
+      const char *utf = env->GetStringUTFChars(jstr, 0);
       str = new std::string(utf);
-      env->ReleaseStringUTFChars((jstring)obj, utf);
+      env->ReleaseStringUTFChars(jstr, utf);
     }
 
     std::string *s = new std::string(*str);
     return s;
   }
   int64_t AsInt() {
+    const char methodName[] = "num";
     JNIEnv *env = getJNIEnv();
-    jclass cls = env->FindClass("java/lang/Integer");
-    jmethodID valueId = env->GetMethodID(cls, "longValue", "()J");
-    long long value = (long long)env->CallLongMethod(obj, valueId);
+    jmethodID mID = MethodID(env, methodName, "()J", CLS_JINT);
+
+    long long value = (long long)env->CallLongMethod(obj, mID);
+    checkJvmException(std::string("failed to call ")
+                          .append(CLS_JINT)
+                          .append(".")
+                          .append(methodName)
+                          .append(" at Node::AsInt()"));
     return (int64_t)(value);
   }
   uint64_t AsUint() {
+    const char methodName[] = "get";
     JNIEnv *env = getJNIEnv();
-    jclass cls = env->FindClass("java/lang/Integer");
-    jmethodID valueId = env->GetMethodID(cls, "intValue", "()I");
-    jlong value = env->CallIntMethod(obj, valueId);
-
-    jmethodID mId = env->GetMethodID(cls, "toUnsignedLong", "(I)J");
-    jlong v = env->CallLongMethod(obj, mId, value);
+    jmethodID mID = MethodID(env, methodName, "()J", CLS_JUINT);
 
-    return (uint64_t)(v);
+    jlong value = env->CallLongMethod(obj, mID);
+    checkJvmException(std::string("failed to call ")
+                          .append(CLS_JUINT)
+                          .append(".")
+                          .append(methodName)
+                          .append(" at Node::AsUint()"));
+    return (uint64_t)(value);
   }
   double AsFloat() {
+    const char methodName[] = "num";
     JNIEnv *env = getJNIEnv();
-    jclass cls = env->FindClass("java/lang/Double");
-    jmethodID valueId = env->GetMethodID(cls, "floatValue", "()F");
-    float value = (float)env->CallFloatMethod(obj, valueId);
+    jmethodID mID = MethodID(env, methodName, "()D", CLS_JFLT);
+
+    double value = (double)env->CallDoubleMethod(obj, mID);
+    checkJvmException(std::string("failed to call ")
+                          .append(CLS_JFLT)
+                          .append(".")
+                          .append(methodName)
+                          .append(" at Node::AsFloat()"));
     return value;
   }
   bool AsBool() {
+    const char methodName[] = "value";
     JNIEnv *env = getJNIEnv();
-    // TODO(bzz) check failures, cache classes, read 'value' filed
-    jclass cls = env->FindClass("java/lang/Boolean");
-    jmethodID valueId = env->GetMethodID(cls, "booleanValue", "()Z");
-    bool value = (bool)env->CallBooleanMethod(obj, valueId);
+    jmethodID mID = MethodID(env, methodName, "()Z", CLS_JBOOL);
+
+    bool value = (bool)env->CallBooleanMethod(obj, mID);
+    checkJvmException(std::string("failed to call ")
+                          .append(CLS_JBOOL)
+                          .append(".")
+                          .append(methodName)
+                          .append(" at Node::AsBool()"));
     return value;
   }
   size_t Size() {
@@ -245,7 +289,7 @@ class Node : public uast::Node<Node *> {
 
     JNIEnv *env = getJNIEnv();
     jstring key = (jstring)ObjectMethod(env, "keyAt", METHOD_JNODE_KEY_AT,
-                                        CLS_JNODE, &obj);
+                                        CLS_JNODE, &obj, i);
 
     const char *k = env->GetStringUTFChars(key, 0);
     std::string *s = new std::string(k);
@@ -258,7 +302,7 @@ class Node : public uast::Node<Node *> {
 
     JNIEnv *env = getJNIEnv();
     jobject val =
-        ObjectMethod(env, "valueAt", METHOD_JNODE_VALUE_AT, CLS_JNODE, &obj);
+        ObjectMethod(env, "valueAt", METHOD_JNODE_VALUE_AT, CLS_JNODE, &obj, i);
     return lookupOrCreate(env->NewGlobalRef(val));  // new ref
   }
 
@@ -287,8 +331,7 @@ class Node : public uast::Node<Node *> {
 
     jstring k = env->NewStringUTF(key.data());
 
-    jobject res =
-        ObjectMethod(env, "add", METHOD_JOBJ_ADD, CLS_JOBJ, &obj, k, v);
+    ObjectMethod(env, "add", METHOD_JOBJ_ADD, CLS_JOBJ, &obj, k, v);
     checkJvmException(
         std::string("failed to call JObject.add() from Node::SetKeyValue(")
             .append(key)
@@ -339,7 +382,7 @@ class Interface : public uast::NodeCreator<Node *> {
   // toJ returns a JVM object associated with a node.
   // Returns a new reference.
   jobject toJ(Node *node) {
-    if (node == nullptr) return nullptr;
+    if (!node) return nullptr;
     jobject obj = getJNIEnv()->NewGlobalRef(node->obj);
     return obj;
   }
@@ -401,9 +444,12 @@ class Context {
   // toJ returns a JVM object associated with a node.
   // Returns a new reference.
   jobject toJ(Node *node) {
-    if (node == nullptr) return nullptr;
+    if (!node) return nullptr;
     return iface->toJ(node);
   }
+  // toNode returns a node associated with a JVM object.
+  // Returns a new reference.
+  Node *toNode(jobject obj) { return iface->lookupOrCreate(obj); }
 
  public:
   Context() {
@@ -427,6 +473,16 @@ class Context {
     return toJ(root);  // new ref
   }
 
+  // Encode serializes UAST.
+  // Creates a new reference.
+  jobject Encode(jobject node, UastFormat format) {
+    if (!assertNotContext(node)) return nullptr;
+
+    Node *n = toNode(node);
+    uast::Buffer data = ctx->Encode(n, format);
+    return asJvmBuffer(data);
+  }
+
   jobject LoadFrom(jobject src) {  // JNode
     JNIEnv *env = getJNIEnv();
 
@@ -474,13 +530,13 @@ JNIEXPORT jobject JNICALL Java_org_bblfsh_client_v2_libuast_Libuast_decode(
     jCtxExt = nullptr;
     delete (ctx);
     delete (p);
-    checkJvmException("failed to instantiate Context class");
+    checkJvmException("failed to instantiate ContextExt class");
   }
 
   return jCtxExt;
 }
 
-// TODO(#86): implement
+// TODO(#83): implement
 JNIEXPORT jobject JNICALL Java_org_bblfsh_client_v2_libuast_Libuast_filter(
     JNIEnv *, jobject, jobject, jstring) {
   return nullptr;
@@ -490,21 +546,31 @@ JNIEXPORT jobject JNICALL Java_org_bblfsh_client_v2_libuast_Libuast_filter(
 //              v2.Context()
 // ==========================================
 
+JNIEXPORT jobject JNICALL Java_org_bblfsh_client_v2_Context_encode(
+    JNIEnv *env, jobject self, jobject node) {
+  UastFormat fmt = UAST_BINARY;  // TODO(bzz): make it argument
+
+  Context *p = getHandle<Context>(env, self, nativeContext);
+  return p->Encode(node, fmt);
+}
+
 JNIEXPORT jlong JNICALL
 Java_org_bblfsh_client_v2_Context_00024_create(JNIEnv *env, jobject self) {
   auto c = new Context();
-  uast::Context<NodeHandle> *ctx;  // TODO(#90): init from c on encode() impl
-  auto p = new ContextExt(ctx);
-  return (long)p;
+  return (long)c;
 }
 
-JNIEXPORT jobject JNICALL Java_org_bblfsh_client_v2_Context_root(JNIEnv *env,
-                                                                 jobject self) {
+// ==========================================
+//              v2.ContextExt()
+// ==========================================
+
+JNIEXPORT jobject JNICALL
+Java_org_bblfsh_client_v2_ContextExt_root(JNIEnv *env, jobject self) {
   ContextExt *p = getHandle<ContextExt>(env, self, nativeContext);
   return p->RootNode();
 }
 
-JNIEXPORT jobject JNICALL Java_org_bblfsh_client_v2_Context_encode(
+JNIEXPORT jobject JNICALL Java_org_bblfsh_client_v2_ContextExt_encode(
     JNIEnv *env, jobject self, jobject node) {
   UastFormat fmt = UAST_BINARY;  // TODO(bzz): make it argument & enum
 
@@ -512,8 +578,8 @@ JNIEXPORT jobject JNICALL Java_org_bblfsh_client_v2_Context_encode(
   return p->Encode(node, fmt);
 }
 
-JNIEXPORT void JNICALL Java_org_bblfsh_client_v2_Context_dispose(JNIEnv *env,
-                                                                 jobject self) {
+JNIEXPORT void JNICALL
+Java_org_bblfsh_client_v2_ContextExt_dispose(JNIEnv *env, jobject self) {
   ContextExt *p = getHandle<ContextExt>(env, self, nativeContext);
   setHandle<ContextExt>(env, self, 0, nativeContext);
   delete p;
diff --git a/src/main/scala/org/bblfsh/client/v2/BblfshClient.scala b/src/main/scala/org/bblfsh/client/v2/BblfshClient.scala
index 369d2b8..23e8c0f 100644
--- a/src/main/scala/org/bblfsh/client/v2/BblfshClient.scala
+++ b/src/main/scala/org/bblfsh/client/v2/BblfshClient.scala
@@ -3,10 +3,8 @@ package org.bblfsh.client.v2
 import java.nio.ByteBuffer
 
 import com.google.protobuf.ByteString
-import com.google.protobuf.duration.Duration
+import gopkg.in.bblfsh.sdk.v2.protocol.driver._
 import io.grpc.ManagedChannelBuilder
-import gopkg.in.bblfsh.sdk.v2.protocol.driver.{ParseRequest, ParseResponse, DriverGrpc, SupportedLanguagesRequest, SupportedLanguagesResponse, VersionRequest, VersionResponse, DriverHostGrpc}
-
 import org.bblfsh.client.v2.libuast.Libuast
 
 
@@ -26,9 +24,9 @@ class BblfshClient(host: String, port: Int, maxMsgSize: Int) {
     * Parses file with a given name and content using 
     * the provided timeout.
     *
-    * @param name file name
+    * @param name    file name
     * @param content file content
-    * @param lang (optional) language to parse, default auto-detect \w enry
+    * @param lang    (optional) language to parse, default auto-detect \w enry
     * @param timeout (disabled) bblfsh request timeout, seconds
     *                Right now this does not have any effect in v2.
     * @return UAST in parse response.
@@ -54,9 +52,9 @@ class BblfshClient(host: String, port: Int, maxMsgSize: Int) {
     * A default timeout of 5 seconds will be applied, same as was done by the server
     * before https://github.com/bblfsh/bblfshd/blob/83166ea0087bfe20c24fc471309f70f422383198/daemon/pool.go#L191
     *
-    * @param name file name
+    * @param name    file name
     * @param content file content
-    * @param lang (optional) language to parse, default auto-detect \w enry
+    * @param lang    (optional) language to parse, default auto-detect \w enry
     * @return UAST in parse response.
     */
   def parse(
@@ -71,10 +69,10 @@ class BblfshClient(host: String, port: Int, maxMsgSize: Int) {
     *
     * Since v1.11, this API exposes the timeout.
     *
-    * @param name file name
+    * @param name    file name
     * @param content file content
     * @param timeout bblfsh request timeout, seconds
-    * @param lang (optional) language to parse, default auto-detect \w enry
+    * @param lang    (optional) language to parse, default auto-detect \w enry
     * @return
     */
   def parseWithTimeout(
@@ -102,9 +100,10 @@ class BblfshClient(host: String, port: Int, maxMsgSize: Int) {
 object BblfshClient {
   val DEFAULT_MAX_MSG_SIZE = 100 * 1024 * 1024 // bytes
 
-  val PreOrder      = 0
-  val PostOrder     = 1
-  val LevelOrder    = 2
+  // TODO(bzz): expose new 'children' order and use enum/case class
+  val PreOrder = 0
+  val PostOrder = 1
+  val LevelOrder = 2
   val PositionOrder = 3
 
   private val libuast = new Libuast
@@ -114,18 +113,17 @@ object BblfshClient {
     maxMsgSize: Int = DEFAULT_MAX_MSG_SIZE
   ): BblfshClient = new BblfshClient(host, port, maxMsgSize)
 
-
   def filter(node: Node, query: String): List[Node] = Libuast.synchronized {
     libuast.filter(node, query)
   }
 
   /**
-   * Decodes bytes from wired format of bblfsh protocol.v2.
-   * Requires a buffer in Direct mode.
-   *
-   * Since v2.
-   */
-  def decode(buf: ByteBuffer): Context = Libuast.synchronized {
+    * Decodes bytes from wired format of bblfsh protocol.v2.
+    * Requires a buffer in Direct mode.
+    *
+    * Since v2.
+    */
+  def decode(buf: ByteBuffer): ContextExt = Libuast.synchronized {
     if (!buf.isDirect()) {
       throw new RuntimeException("Only directly-allocated buffer decoding is supported.")
     }
@@ -135,10 +133,10 @@ object BblfshClient {
   // Enables API: resp.uast.decode()
   implicit class UastMethods(val buf: ByteString) {
     /**
-     * Decodes bytes from wired format of bblfsh protocol.v2.
-     * Copies a buffer in Direct mode.
-     */
-    def decode(): Context = {
+      * Decodes bytes from wired format of bblfsh protocol.v2.
+      * Copies a buffer in Direct mode.
+      */
+    def decode(): ContextExt = {
       val bufDirectCopy = ByteBuffer.allocateDirect(buf.size)
       buf.copyTo(bufDirectCopy)
       BblfshClient.decode(bufDirectCopy)
diff --git a/src/main/scala/org/bblfsh/client/v2/Context.scala b/src/main/scala/org/bblfsh/client/v2/Context.scala
deleted file mode 100644
index fe84523..0000000
--- a/src/main/scala/org/bblfsh/client/v2/Context.scala
+++ /dev/null
@@ -1,25 +0,0 @@
-package org.bblfsh.client.v2
-	
-import java.nio.ByteBuffer
-
-case class Context(nativeContext: Long) {
-    def this() = this(Context.create())
-
-    @native def root(): Node
-    @native def encode(n: Node): ByteBuffer
-    @native def dispose()
-
-    @native def filter()
-
-    // TODO(bzz): add loading of the root node, after clarifying when it's needed
-    // https://github.com/bblfsh/client-python/blob/master/bblfsh/pyuast.cc#L364
-    // @native def load(): ?
-
-    override def finalize(): Unit = {
-        this.dispose()
-    }
-}
-
-object Context {
-    @native def create(): Long
-}
diff --git a/src/main/scala/org/bblfsh/client/v2/ContextExt.scala b/src/main/scala/org/bblfsh/client/v2/ContextExt.scala
new file mode 100644
index 0000000..d3185f2
--- /dev/null
+++ b/src/main/scala/org/bblfsh/client/v2/ContextExt.scala
@@ -0,0 +1,41 @@
+package org.bblfsh.client.v2
+	
+import java.nio.ByteBuffer
+
+/**
+  * Represents Go-side results of Libuast.decode()
+  *
+  * This is equivalent of pyuast.ContextExt API
+  */
+case class ContextExt(nativeContext: Long) {
+    @native def root(): Node
+    // @native def load() // TODO(bzz): implement after clarifying when it's needed
+    @native def filter()
+    @native def encode(n: Node): ByteBuffer
+
+    @native def dispose()
+    override def finalize(): Unit = {
+        this.dispose()
+    }
+}
+
+
+/**
+  * Represents JVM-side constructed tree
+  *
+  * This is equivalent of pyuast.Context API
+  */
+case class Context(nativeContext: Long) {
+    @native def root(): JNode
+    @native def filter()
+    @native def encode(n: JNode): ByteBuffer
+
+    @native def dispose()
+    override def finalize(): Unit = {
+        this.dispose()
+    }
+}
+object Context {
+    @native def create(): Long
+    def apply(): Context = new Context(create())
+}
diff --git a/src/main/scala/org/bblfsh/client/v2/libuast/Libuast.scala b/src/main/scala/org/bblfsh/client/v2/libuast/Libuast.scala
index a1ec257..40e106a 100644
--- a/src/main/scala/org/bblfsh/client/v2/libuast/Libuast.scala
+++ b/src/main/scala/org/bblfsh/client/v2/libuast/Libuast.scala
@@ -1,14 +1,13 @@
 package org.bblfsh.client.v2.libuast
 
-import org.bblfsh.client.v2.Node
-import org.bblfsh.client.v2.Context
+import org.bblfsh.client.v2.{ContextExt, JNode, Node}
 
 import scala.collection.Iterator
 import java.io.File
 import java.nio.file.Paths
 import java.nio.ByteBuffer
 
-import org.apache.commons.io.{IOUtils, FileUtils}
+import org.apache.commons.io.{FileUtils, IOUtils}
 
 object Libuast {
   final var loaded = false
@@ -86,6 +85,6 @@ class Libuast {
   //   new Libuast.UastIterator(node, treeOrder)
   // }
 
-  @native def decode(buf: ByteBuffer): Context
+  @native def decode(buf: ByteBuffer): ContextExt
   @native def filter(node: Node, query: String): List[Node]
 }
diff --git a/src/test/scala/org/bblfsh/client/v2/BblfshClientLoadTest.scala b/src/test/scala/org/bblfsh/client/v2/BblfshClientLoadTest.scala
index e143fa4..c91eb4d 100644
--- a/src/test/scala/org/bblfsh/client/v2/BblfshClientLoadTest.scala
+++ b/src/test/scala/org/bblfsh/client/v2/BblfshClientLoadTest.scala
@@ -1,5 +1,7 @@
 package org.bblfsh.client.v2
 
+import java.nio.ByteBuffer
+
 
 class BblfshClientLoadTest extends BblfshClientBaseTest {
 
@@ -34,32 +36,41 @@ class BblfshClientLoadTest extends BblfshClientBaseTest {
     root.children.foreach(println)
   }
 
-  // TODO(#90) a stub for testing JNode encoding impl
-  /*"Loading Go -> JVM for a simple encoded tree" should "bring JNode tree to memory" in {
-    val rootTree: JNode = JArray(Buffer(
-      JObject(Buffer(
+  "Loading Go -> JVM for a simple encoded tree" should "bring JNode tree to memory" in {
+    val rootTree: JNode = JArray(
+      JObject(
         "k1" -> JString("v1")
-      )),
+      ),
       JString("test")
-    ))
+    )
+
+    rootTree.size should be (2)
 
     val ctx = Context()
+    val bb: ByteBuffer = ctx.encode(rootTree)
 
-    ctx.encode(rootTree)
-  }*/
+    bb should not be (null)
+  }
 
-  // TODO(#90) a stub for more extensive testing of JNode encoding impl
-  /*"Decoding, loading & encoding to different context" should "produce the same results" in {
+  "Decoding, loading & encoding to different context" should "produce the same results" in {
+    // decode -> load -> encode, and compare bytes
     val uast = resp.uast.decode()
     val rootNode: Node = uast.root()
 
     println(s"Loading $rootNode")
     val root = rootNode.load()
-
     val ctx = Context()
     val data = ctx.encode(root)
 
-    data shouldBe equal resp.uast
-  }*/
+    data should equal (resp.uast.asReadOnlyByteBuffer())
+
+    // decode -> load -> encoded -> decode -> load, and compare trees
+    val uast2 = BblfshClient.decode(data)
+    val rootNode2: Node = uast2.root()
+    println(s"Loading $rootNode2")
+    val root2 = rootNode2.load()
+
+    root2 should equal (root)
+  }
 
 }
diff --git a/src/test/scala/org/bblfsh/client/v2/BblfshClientParseTest.scala b/src/test/scala/org/bblfsh/client/v2/BblfshClientParseTest.scala
index bb0ad6e..694c46c 100644
--- a/src/test/scala/org/bblfsh/client/v2/BblfshClientParseTest.scala
+++ b/src/test/scala/org/bblfsh/client/v2/BblfshClientParseTest.scala
@@ -35,7 +35,7 @@ class BblfshClientParseTest extends BblfshClientBaseTest {
   }
 
   "Encoding back the RootNode of decoded UAST" should "produce same bytes" in {
-    val uastCtx: Context = resp.uast.decode()
+    val uastCtx: ContextExt = resp.uast.decode()
     val rootNode: Node = uastCtx.root()
     println(s"Root node: $rootNode")