Fix it

src/main/java/org/apache/sysds/runtime/util/DoubleBufferingOutputStream.java

@@ -23,11 +23,14 @@
 import java.io.IOException;
 import java.io.OutputStream;
 import java.util.concurrent.Callable;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
 import java.util.concurrent.Future;
 
 import org.apache.commons.lang3.concurrent.ConcurrentUtils;
 
 public class DoubleBufferingOutputStream extends FilterOutputStream {
+	protected ExecutorService _pool = Executors.newSingleThreadExecutor();
 	protected Future<?>[] _locks;
 	protected byte[][] _buff;
 	private int _pos;
@@ -66,7 +69,7 @@ public void write(byte[] b, int off, int len)
 				System.arraycopy(b, off, _buff[_pos], 0, len);
 
 				//submit write request 
-				_locks[_pos] = CommonThreadPool.getDynamicPool().submit(new WriteTask(_buff[_pos], len));
+				_locks[_pos] = _pool.submit(new WriteTask(_buff[_pos], len));
 				_pos = (_pos+1) % _buff.length;
 			}
 		}
@@ -100,6 +103,7 @@ public void flush() throws IOException {
 
 	@Override
 	public void close() throws IOException {
+		_pool.shutdown();
 		super.close();
 	}
 

src/test/java/org/apache/sysds/test/functions/paramserv/ParamservSyntaxTest.java

@@ -93,9 +93,11 @@ public void testParamservMinimumVersion() {
 
 	private void runDMLTest(String testname, boolean exceptionExpected, Class<?> exceptionClass, String errmsg) {
 		TestConfiguration config = getTestConfiguration(testname);
+		setOutputBuffering(true);
 		loadTestConfiguration(config);
 		programArgs = new String[] { "-explain" };
 		fullDMLScriptName = HOME + testname + ".dml";
 		runTest(true, exceptionExpected, exceptionClass, errmsg, -1);
+		setOutputBuffering(false);
 	}
 }