Angel-serving 加载模型NPE错误

## Angel-Serving NPE错误

### 问题

  按官方文档加载了自己定义的模型，经测试模型无问题，然后调用angel-serving的predictAPI出现如下错误.

```
20/01/08 15:32:27 INFO common.ServiceImpl$ : modelSpec: fm, value: 6

20/01/08 15:32:27 INFO common.ServiceImpl$ : servableHandle {name: fm, version: 6}
java.lang.NullPointerException
at com.tencent.angel.mlcore.variable.EmbedUtils$$anonfun$9.apply(EmbedUtils.scala:144)
at com.tencent.angel.mlcore.variable.EmbedUtils$$anonfun$9.apply(EmbedUtils.scala:138)
at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:234)
at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:234)
at scala.collection.IndexedSeqOptimized$class.foreach(IndexedSeqOptimized.scala:33)
at scala.collection.mutable.ArrayOps$ofInt.foreach(ArrayOps.scala:234)
at scala.collection.TraversableLike$class.map(TraversableLike.scala:234)
at scala.collection.mutable.ArrayOps$ofInt.map(ArrayOps.scala:234)
at com.tencent.angel.mlcore.variable.EmbedUtils$.oneHotAssemble(EmbedUtils.scala:138)
at com.tencent.angel.mlcore.variable.EmbedUtils$$anonfun$1.apply(EmbedUtils.scala:50)
at com.tencent.angel.mlcore.variable.EmbedUtils$$anonfun$1.apply(EmbedUtils.scala:41)
at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:234)
at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:234)
at scala.collection.IndexedSeqOptimized$class.foreach(IndexedSeqOptimized.scala:33)
at scala.collection.mutable.ArrayOps$ofInt.foreach(ArrayOps.scala:234)
at scala.collection.TraversableLike$class.map(TraversableLike.scala:234)
at scala.collection.mutable.ArrayOps$ofInt.map(ArrayOps.scala:234)
at com.tencent.angel.mlcore.variable.EmbedUtils$.geneMatrix(EmbedUtils.scala:41)
at com.tencent.angel.mlcore.local.variables.LocalEmbedVariable.doPull(LocalEmbedVariable.scala:60)
at com.tencent.angel.mlcore.variable.Variable.pull(Variable.scala:232)
at com.tencent.angel.mlcore.local.LocalVariableManager$$anonfun$pullALL$1.apply(LocalVariableManager.scala:43)
at com.tencent.angel.mlcore.local.LocalVariableManager$$anonfun$pullALL$1.apply(LocalVariableManager.scala:41)
at scala.collection.Iterator$class.foreach(Iterator.scala:893)
at scala.collection.AbstractIterator.foreach(Iterator.scala:1336)
at scala.collection.IterableLike$class.foreach(IterableLike.scala:72)
at scala.collection.AbstractIterable.foreach(Iterable.scala:54)
at com.tencent.angel.mlcore.local.LocalVariableManager.pullALL(LocalVariableManager.scala:41)
at com.tencent.angel.mlcore.MLModel.pullParams(MLModel.scala:116)
at com.tencent.angel.mlcore.local.LocalModel.predict(LocalModel.scala:50)
at com.tencent.angel.serving.servables.angel.AngelSavedModelBundle.runPredict(AngelSavedModelBundle.scala:67)
at com.tencent.angel.serving.servables.common.ServiceImpl$.predict(ServiceImpl.scala:57)
at com.tencent.angel.serving.service.jersey.resources.HttpRestApiHandler.processPredictRequest(HttpRestApiHandler.scala:152)
at com.tencent.angel.serving.service.jersey.resources.HttpRestApiHandler.processPredictionServiceRequest(HttpRestApiHandler.scala:126)
at sun.reflect.GeneratedMethodAccessor12.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.sun.jersey.spi.container.JavaMethodInvokerFactory$1.invoke(JavaMethodInvokerFactory.java:60)
at com.sun.jersey.server.impl.model.method.dispatch.AbstractResourceMethodDispatchProvider$ResponseOutInvoker._dispatch(AbstractResourceMethodDispatchProvider.java:205)
at com.sun.jersey.server.impl.model.method.dispatch.ResourceJavaMethodDispatcher.dispatch(ResourceJavaMethodDispatcher.java:75)
at com.sun.jersey.server.impl.uri.rules.HttpMethodRule.accept(HttpMethodRule.java:302)
at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)
at com.sun.jersey.server.impl.uri.rules.ResourceClassRule.accept(ResourceClassRule.java:108)
at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)
at com.sun.jersey.server.impl.uri.rules.RootResourceClassesRule.accept(RootResourceClassesRule.java:84)
at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1542)
at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1473)
at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1419)
at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1409)
at com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:409)
at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:558)
at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:733)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:848)
at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:684)
at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:501)
at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1086)
at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:427)
at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1020)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:135)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:116)
at org.eclipse.jetty.server.Server.handle(Server.java:370)
at org.eclipse.jetty.server.AbstractHttpConnection.handleRequest(AbstractHttpConnection.java:494)
at org.eclipse.jetty.server.AbstractHttpConnection.content(AbstractHttpConnection.java:984)
at org.eclipse.jetty.server.AbstractHttpConnection$RequestHandler.content(AbstractHttpConnection.java:1045)
at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:861)
at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:236)
at org.eclipse.jetty.server.AsyncHttpConnection.handle(AsyncHttpConnection.java:82)
at org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint.java:696)
at org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.java:53)
at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:608)
at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:543)
at java.lang.Thread.run(Thread.java:748)
```

  经排查后，发现**LocalEmbedVariable.scala**下列代码存在问题.

```
protected override def doPull(epoch: Int, indices: Vector = null): Unit = {
embeddings.clear()

if (indices != null) {
indices.getStorage match {
case s: IntIntDenseVectorStorage =>
s.getValues.foreach { idx => embeddings.put(idx.toLong, storage.getRow(idx)) }
case s: IntLongDenseVectorStorage =>
s.getValues.foreach { idx => embeddings.put(idx, storage.getRow(idx.toInt)) }
}
} else {
(0 until numRows).foreach { idx =>
embeddings.put(idx.toLong, storage.getRow(idx))
}
}

val matStats = EmbedUtils.geneMatrix(placeHolder, assembleHint, embeddings)
matrix = matStats._1
assembleStats = matStats._2
}
```

  当storage 实例为MapMatrix时，其对应属性mapMatrix声明如下:

```
protected HashMap mapMatrix;
```

  而上述storage.getRow(idx) idx为Int时获取不到相关值，因为在Java中包装类型Long和Integer各自维护了缓存. 改为使用Long类型则能获取到，如下是改动后的代码.

```
protected override def doPull(epoch: Int, indices: Vector = null): Unit = {
embeddings.clear()

if (indices != null) {
indices.getStorage match {
case s: IntIntDenseVectorStorage =>
s.getValues.foreach { idx => embeddings.put(idx.toLong, storage.getRow(idx)) }
case s: IntLongDenseVectorStorage =>
s.getValues.foreach { idx => embeddings.put(idx, storage.getRow(idx.toInt)) }
}
} else {
(0 until numRows).foreach { idx =>
if ( storage.isInstanceOf[MapMatrix[Vector]]) {
val mapStorage = storage.asInstanceOf[MapMatrix[Vector]]
embeddings.put(idx.toLong, mapStorage.getRow(idx.toLong))
}else{
embeddings.put(idx.toLong, storage.getRow(idx))
}

}
}
}
```