Add modifications to hadoop compatibility package as required for parquet testing.

stratosphere-addons/hadoop-compatibility/src/main/java/eu/stratosphere/hadoopcompatibility/HadoopInputSplitWrapper.java

@@ -60,9 +60,11 @@ public class HadoopInputSplitWrapper implements InputSplit {
 		this.hadoopInputSplitTypeName = in.readUTF();
 		if(hadoopInputSplit == null) {
 			try {
-				Class inputSplit = Class.forName(hadoopInputSplitTypeName );
+				Class<? extends org.apache.hadoop.io.Writable> inputSplit = 
+						Class.forName(hadoopInputSplitTypeName).asSubclass(org.apache.hadoop.io.Writable.class);
 				this.hadoopInputSplit = (org.apache.hadoop.mapred.InputSplit) WritableFactories.newInstance( inputSplit );
-			} catch (Exception e) {
+			}
+			catch (Exception e) {
 				throw new RuntimeException("Unable to create InputSplit", e);
 			}
 		}

stratosphere-addons/hadoop-compatibility/src/main/java/eu/stratosphere/hadoopcompatibility/datatypes/DefaultHadoopTypeConverter.java

@@ -19,6 +19,7 @@ import org.apache.hadoop.io.DoubleWritable;
 import org.apache.hadoop.io.FloatWritable;
 import org.apache.hadoop.io.IntWritable;
 import org.apache.hadoop.io.LongWritable;
+import org.apache.hadoop.io.NullWritable;
 import org.apache.hadoop.io.Text;
 
 import eu.stratosphere.types.BooleanValue;
@@ -27,6 +28,7 @@ import eu.stratosphere.types.DoubleValue;
 import eu.stratosphere.types.FloatValue;
 import eu.stratosphere.types.IntValue;
 import eu.stratosphere.types.LongValue;
+import eu.stratosphere.types.NullValue;
 import eu.stratosphere.types.Record;
 import eu.stratosphere.types.StringValue;
 import eu.stratosphere.types.Value;
@@ -35,18 +37,17 @@ import eu.stratosphere.types.Value;
 /**
  * Converter for the default hadoop writables.
  * Key will be in field 0, Value in field 1 of a Stratosphere Record.
- *
  */
 public class DefaultHadoopTypeConverter<K, V> implements HadoopTypeConverter<K, V> {
 	private static final long serialVersionUID = 1L;
 
 	@Override
 	public void convert(Record stratosphereRecord, K hadoopKey, V hadoopValue) {
-		stratosphereRecord.setField(0, convert(hadoopKey)); 
-		stratosphereRecord.setField(1, convert(hadoopValue)); 
+		stratosphereRecord.setField(0, convert(hadoopKey));
+		stratosphereRecord.setField(1, convert(hadoopValue));
 	}
 	
-	private Value convert(Object hadoopType) {
+	protected Value convert(Object hadoopType) {
 		if(hadoopType instanceof org.apache.hadoop.io.LongWritable ) {
 			return new LongValue(((LongWritable)hadoopType).get());
 		}
@@ -68,6 +69,9 @@ public class DefaultHadoopTypeConverter<K, V> implements HadoopTypeConverter<K,
 		if(hadoopType instanceof org.apache.hadoop.io.ByteWritable) {
 			return new ByteValue(((ByteWritable)hadoopType).get());
 		}
+		if (hadoopType instanceof NullWritable) {
+			return NullValue.getInstance();
+		}
 		
 		throw new RuntimeException("Unable to convert Hadoop type ("+hadoopType.getClass().getCanonicalName()+") to Stratosphere.");
 	}

stratosphere-addons/hadoop-compatibility/src/main/java/eu/stratosphere/hadoopcompatibility/datatypes/DefaultStratosphereTypeConverter.java

@@ -54,6 +54,7 @@ public class DefaultStratosphereTypeConverter<K,V> implements StratosphereTypeCo
 		return convert(stratosphereRecord, 1, this.valueClass);
 	}
 
+	@SuppressWarnings("unchecked")
 	private<T> T convert(Record stratosphereType, int pos, Class<T> hadoopType) {
 		if(hadoopType == LongWritable.class ) {
 			return (T) new LongWritable((stratosphereType.getField(pos, LongValue.class)).getValue());