From 3e02c0a7c39ea208c973b591cb97902533ad4e5f Mon Sep 17 00:00:00 2001
From: Gilles Gouaillardet <gilles@rist.or.jp>
Date: Tue, 18 Aug 2015 09:47:28 +0900
Subject: [PATCH] java/Prequest: keep a pointer to the buffer this prevents
 garbage collector from freeing the buffer

---
 ompi/mpi/java/java/Comm.java     | 10 +++++-----
 ompi/mpi/java/java/Prequest.java | 14 +++++++++++++-
 2 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/ompi/mpi/java/java/Comm.java b/ompi/mpi/java/java/Comm.java
index c8693153f2a..2b796985ef1 100644
--- a/ompi/mpi/java/java/Comm.java
+++ b/ompi/mpi/java/java/Comm.java
@@ -769,7 +769,7 @@ public final Prequest sendInit(Buffer buf, int count,
 	{
 		MPI.check();
 		assertDirectBuffer(buf);
-		return new Prequest(sendInit(handle, buf, count, type.handle, dest, tag));
+		return new Prequest(sendInit(handle, buf, count, type.handle, dest, tag), buf);
 	}
 
 	private native long sendInit(
@@ -794,7 +794,7 @@ public final Prequest bSendInit(Buffer buf, int count,
 	{
 		MPI.check();
 		assertDirectBuffer(buf);
-		return new Prequest(bSendInit(handle, buf, count, type.handle, dest, tag));
+		return new Prequest(bSendInit(handle, buf, count, type.handle, dest, tag), buf);
 	}
 
 	private native long bSendInit(
@@ -819,7 +819,7 @@ public final Prequest sSendInit(Buffer buf, int count,
 	{
 		MPI.check();
 		assertDirectBuffer(buf);
-		return new Prequest(sSendInit(handle, buf, count, type.handle, dest, tag));
+		return new Prequest(sSendInit(handle, buf, count, type.handle, dest, tag), buf);
 	}
 
 	private native long sSendInit(
@@ -844,7 +844,7 @@ public final Prequest rSendInit(Buffer buf, int count,
 	{
 		MPI.check();
 		assertDirectBuffer(buf);
-		return new Prequest(rSendInit(handle, buf, count, type.handle, dest, tag));
+		return new Prequest(rSendInit(handle, buf, count, type.handle, dest, tag), buf);
 	}
 
 	private native long rSendInit(
@@ -869,7 +869,7 @@ public final Prequest recvInit(Buffer buf, int count,
 	{
 		MPI.check();
 		assertDirectBuffer(buf);
-		return new Prequest(recvInit(handle, buf, count, type.handle, source, tag));
+		return new Prequest(recvInit(handle, buf, count, type.handle, source, tag), buf);
 	}
 
 	private native long recvInit(
diff --git a/ompi/mpi/java/java/Prequest.java b/ompi/mpi/java/java/Prequest.java
index 94b36978392..1ea96ba930a 100644
--- a/ompi/mpi/java/java/Prequest.java
+++ b/ompi/mpi/java/java/Prequest.java
@@ -11,6 +11,8 @@
  *                         All rights reserved.
  * Copyright (c) 2015      Los Alamos National Security, LLC. All rights
  *                         reserved.
+ * Copyright (c) 2015      Research Organization for Information Science
+ *                         and Technology (RIST). All rights reserved.
  * $COPYRIGHT$
  *
  * Additional copyrights may follow
@@ -47,18 +49,28 @@
 
 package mpi;
 
+import java.nio.Buffer;
+
 /**
  * Persistent request object.
  */
 public final class Prequest extends Request
 {
+	/**
+	 * Buffer used internally by the persistent request
+	 * maintain a pointer to the buffer to ensure it
+	 * cannot be free'd by the garbage collector
+	 */
+	private Buffer buffer;
+
 	/**
 	 * Constructor used by {@code sendInit}, etc.
 	 * @param handle	Handle for the Prequest object
 	 */
-	protected Prequest(long handle)
+	protected Prequest(long handle, Buffer buffer)
 	{
 		super(handle);
+		this.buffer = buffer;
 	}
 
 	/**