pgjdbc logical replication client throwing exception

hi,

I am trying to implement logical replication stream API of postgresql.
I am facing unusual connection breakdown problem. Here is the simple code
that I am
using to read WAL file:

String url = "jdbc:postgresql://pcnode2:5432/benchmarksql";
Properties props = new Properties();
PGProperty.USER.set(props, "benchmarksql");
PGProperty.PASSWORD.set(props, "benchmarksql");
PGProperty.ASSUME_MIN_SERVER_VERSION.set(props, "9.4");
PGProperty.REPLICATION.set(props, "database");
PGProperty.PREFER_QUERY_MODE.set(props, "simple");

Connection conn = DriverManager.getConnection(url, props);
PGConnection replConnection = conn.unwrap(PGConnection.class);

PGReplicationStream stream = replConnection.getReplicationAPI()
.replicationStream().logical()
.withSlotName("replication_slot3")
.withSlotOption("include-xids", true)
.withSlotOption("include-timestamp", "on")
.withSlotOption("skip-empty-xacts", true)
.withStatusInterval(20, TimeUnit.MILLISECONDS).start();
while (true) {

ByteBuffer msg = stream.read();

if (msg == null) {
TimeUnit.MILLISECONDS.sleep(10L);
continue;
}

int offset = msg.arrayOffset();
byte[] source = msg.array();
int length = source.length - offset;
String data = new String(source, offset, length);
* System.out.println(data);*

stream.setAppliedLSN(stream.getLastReceiveLSN());
stream.setFlushedLSN(stream.getLastReceiveLSN());

}

Even the slightest modification in the code like commenting
*System.out.println(data)*;
which is just printing the data in the console, causes connection breakdown
problem with
following error msg

org.postgresql.util.PSQLException: Database connection failed when reading
from copy
at org.postgresql.core.v3.QueryExecutorImpl.readFromCopy(QueryE
xecutorImpl.java:1028)
at org.postgresql.core.v3.CopyDualImpl.readFromCopy(CopyDualImp
l.java:41)
at org.postgresql.core.v3.replication.V3PGReplicationStream.rec
eiveNextData(V3PGReplicationStream.java:155)
at org.postgresql.core.v3.replication.V3PGReplicationStream.rea
dInternal(V3PGReplicationStream.java:124)
at org.postgresql.core.v3.replication.V3PGReplicationStream.
read(V3PGReplicationStream.java:70)
at Server.main(Server.java:52)
Caused by: java.net.SocketException: Socket closed
at java.net.SocketInputStream.socketRead0(Native Method)
at java.net.SocketInputStream.socketRead(SocketInputStream.java:116)
at java.net.SocketInputStream.read(SocketInputStream.java:171)
at java.net.SocketInputStream.read(SocketInputStream.java:141)
at org.postgresql.core.VisibleBufferedInputStream.readMore(Visi
bleBufferedInputStream.java:140)
at org.postgresql.core.VisibleBufferedInputStream.ensureBytes(V
isibleBufferedInputStream.java:109)
at org.postgresql.core.VisibleBufferedInputStream.read(VisibleB
ufferedInputStream.java:191)
at org.postgresql.core.PGStream.receive(PGStream.java:495)
at org.postgresql.core.PGStream.receive(PGStream.java:479)
at org.postgresql.core.v3.QueryExecutorImpl.processCopyResults(
QueryExecutorImpl.java:1161)
at org.postgresql.core.v3.QueryExecutorImpl.readFromCopy(QueryE
xecutorImpl.java:1026)
... 5 more

I am trying to implement some logic like filtering out the unrelated table
after reading log.
But due to this unusual behavior I couldn't implement properly.
Can somebody give me some hint how to solve this problem.

Thank you.