diff --git a/pregelix/pregelix-dataflow/pom.xml b/pregelix/pregelix-dataflow/pom.xml
index 31b6adc..107f059 100644
--- a/pregelix/pregelix-dataflow/pom.xml
+++ b/pregelix/pregelix-dataflow/pom.xml
@@ -1,14 +1,15 @@
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
 	<modelVersion>4.0.0</modelVersion>
 	<artifactId>pregelix-dataflow</artifactId>
 	<packaging>jar</packaging>
 	<name>pregelix-dataflow</name>
 
 	<parent>
-    		<groupId>edu.uci.ics.hyracks</groupId>
-    		<artifactId>pregelix</artifactId>
-    		<version>0.2.3-SNAPSHOT</version>
-  	</parent>
+		<groupId>edu.uci.ics.hyracks</groupId>
+		<artifactId>pregelix</artifactId>
+		<version>0.2.3-SNAPSHOT</version>
+	</parent>
 
 
 	<properties>
@@ -103,13 +104,6 @@
 			<version>0.2.3-SNAPSHOT</version>
 		</dependency>
 		<dependency>
-			<groupId>org.apache.hadoop</groupId>
-			<artifactId>hadoop-core</artifactId>
-			<version>0.20.2</version>
-			<type>jar</type>
-			<scope>compile</scope>
-		</dependency>
-		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-storage-am-common</artifactId>
 			<version>0.2.3-SNAPSHOT</version>
@@ -144,12 +138,5 @@
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
-		<dependency>
-			<groupId>edu.uci.ics.hyracks</groupId>
-			<artifactId>hyracks-hdfs</artifactId>
-			<version>0.2.3-SNAPSHOT</version>
-			<type>jar</type>
-			<scope>compile</scope>
-		</dependency>
 	</dependencies>
 </project>
diff --git a/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/HDFSFileWriteOperatorDescriptor.java b/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/HDFSFileWriteOperatorDescriptor.java
index c25e4c6..0133d76 100644
--- a/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/HDFSFileWriteOperatorDescriptor.java
+++ b/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/HDFSFileWriteOperatorDescriptor.java
@@ -64,17 +64,20 @@
         return new AbstractUnaryInputSinkOperatorNodePushable() {
             private RecordDescriptor rd0;
             private FrameDeserializer frameDeserializer;
-            private Configuration conf = confFactory.createConfiguration();
+            private Configuration conf;
             private VertexWriter vertexWriter;
             private TaskAttemptContext context;
             private String TEMP_DIR = "_temporary";
+            private ClassLoader ctxCL;
 
             @Override
             public void open() throws HyracksDataException {
                 rd0 = inputRdFactory == null ? recordDescProvider.getInputRecordDescriptor(getActivityId(), 0)
                         : inputRdFactory.createRecordDescriptor();
                 frameDeserializer = new FrameDeserializer(ctx.getFrameSize(), rd0);
+                ctxCL = Thread.currentThread().getContextClassLoader();
                 Thread.currentThread().setContextClassLoader(this.getClass().getClassLoader());
+                conf = confFactory.createConfiguration();
 
                 VertexOutputFormat outputFormat = BspUtils.createVertexOutputFormat(conf);
                 TaskAttemptID tid = new TaskAttemptID("", 0, true, partition, 0);
@@ -107,7 +110,7 @@
 
             @Override
             public void fail() throws HyracksDataException {
-
+                Thread.currentThread().setContextClassLoader(ctxCL);
             }
 
             @Override
@@ -151,6 +154,8 @@
                     dfs.rename(srcFile, filePath);
                 } catch (IOException e) {
                     throw new HyracksDataException(e);
+                } finally {
+                    Thread.currentThread().setContextClassLoader(ctxCL);
                 }
             }
 
diff --git a/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/VertexFileScanOperatorDescriptor.java b/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/VertexFileScanOperatorDescriptor.java
index cb0e339..a38b19e 100644
--- a/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/VertexFileScanOperatorDescriptor.java
+++ b/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/VertexFileScanOperatorDescriptor.java
@@ -25,8 +25,6 @@
 import org.apache.hadoop.io.Writable;
 import org.apache.hadoop.io.WritableComparable;
 import org.apache.hadoop.mapreduce.InputSplit;
-import org.apache.hadoop.mapreduce.Mapper;
-import org.apache.hadoop.mapreduce.Mapper.Context;
 import org.apache.hadoop.mapreduce.TaskAttemptContext;
 import org.apache.hadoop.mapreduce.TaskAttemptID;
 import org.apache.hadoop.mapreduce.lib.input.FileSplit;
@@ -43,6 +41,7 @@
 import edu.uci.ics.hyracks.dataflow.common.comm.util.FrameUtils;
 import edu.uci.ics.hyracks.dataflow.std.base.AbstractSingleActivityOperatorDescriptor;
 import edu.uci.ics.hyracks.dataflow.std.base.AbstractUnaryOutputSourceOperatorNodePushable;
+import edu.uci.ics.hyracks.hdfs.ContextFactory;
 import edu.uci.ics.hyracks.hdfs2.dataflow.FileSplitsFactory;
 import edu.uci.ics.pregelix.api.graph.Vertex;
 import edu.uci.ics.pregelix.api.io.VertexInputFormat;
@@ -83,12 +82,15 @@
         final List<FileSplit> splits = splitsFactory.getSplits();
 
         return new AbstractUnaryOutputSourceOperatorNodePushable() {
-            private Configuration conf = confFactory.createConfiguration();
+            private ClassLoader ctxCL;
+            private ContextFactory ctxFactory = new ContextFactory();
 
             @Override
             public void initialize() throws HyracksDataException {
+                ctxCL = Thread.currentThread().getContextClassLoader();
                 try {
                     Thread.currentThread().setContextClassLoader(this.getClass().getClassLoader());
+                    Configuration conf = confFactory.createConfiguration();
                     writer.open();
                     for (int i = 0; i < scheduledLocations.length; i++) {
                         if (scheduledLocations[i].equals(ctx.getJobletContext().getApplicationContext().getNodeId())) {
@@ -102,12 +104,14 @@
                                     continue;
                                 }
                             }
-                            loadVertices(ctx, i);
+                            loadVertices(ctx, conf, i);
                         }
                     }
                     writer.close();
                 } catch (Exception e) {
                     throw new HyracksDataException(e);
+                } finally {
+                    Thread.currentThread().setContextClassLoader(ctxCL);
                 }
             }
 
@@ -122,8 +126,9 @@
              * @throws InterruptedException
              */
             @SuppressWarnings("unchecked")
-            private void loadVertices(final IHyracksTaskContext ctx, int splitId) throws IOException,
-                    ClassNotFoundException, InterruptedException, InstantiationException, IllegalAccessException {
+            private void loadVertices(final IHyracksTaskContext ctx, Configuration conf, int splitId)
+                    throws IOException, ClassNotFoundException, InterruptedException, InstantiationException,
+                    IllegalAccessException {
                 ByteBuffer frame = ctx.allocateFrame();
                 FrameTupleAppender appender = new FrameTupleAppender(ctx.getFrameSize());
                 appender.reset(frame, true);
@@ -141,8 +146,7 @@
                 /**
                  * set context
                  */
-                Context mapperContext = new Mapper().new Context(conf, new TaskAttemptID(), null, null, null, null,
-                        splits.get(splitId));
+                TaskAttemptContext mapperContext = ctxFactory.createContext(conf, splits.get(splitId));
                 Vertex.setContext(mapperContext);
 
                 /**