Function to fill JVM/Java Heap, Java options to automatically create a Heapdump on that event and a companion script to upload resulting files to S3

ConsumeHeap.java

import java.io.IOException;
import java.util.Vector;

/**
 * Created by moshee
 * on: 07/06/17
 * to compile in place: `javac ConsumeHeap.java`
 * Execute: `java -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=/var/log/app-`date +%s`-pid$$.hprof -XX:OnOutOfMemoryError=/opt/app/bin/upload_dump_s3.sh -Xmx2m ConsumeHeap`
 * HeapDumpOnOutOfMemoryError specifies to automatically create a dump when OOM occures
 * HeapDumpPath supplies a path to put that file
 * OnOutOfMemoryError specifies a script(s) to run after dump is created (in this case upload_dump_s3.sh)
 */
public class ConsumeHeap {

    public static void main(String[] args) throws IOException {
        Vector v = new Vector();
        while (true)
        {
            byte b[] = new byte[1048576];
            v.add(b);
            Runtime rt = Runtime.getRuntime();
            System.out.println( "free memory: " + rt.freeMemory() );
        }

    }
}

upload_dump_s3.sh

#!/bin/bash
timestamp()
{
 date +"%Y-%m-%d %T"
}

LOG_FILE="/var/log/s3_upload.log"
exec > >(tee -a $LOG_FILE) # directs stdout to log file
exec 2>&1 # and also to console

ec2InstanceId=`hostname`

export AWS_ACCESS_KEY_ID=$HEAPDUMP_UP_AWS_ACCESS_KEY_ID
export AWS_SECRET_ACCESS_KEY=$HEAPDUMP_UP_AWS_SECRET_ACCESS_KEY
export AWS_DEFAULT_REGION=us-east-1

NOW=$(date +"%Y%m%d%H%M%S")
expirationDate=$(date -d $(date +"%Y/%m/%"d)+" 30 days" +%Y/%m/%d)

echo "$(timestamp): look for heap dumps to upload "

cd /var/log/

for hprof_file in *.hprof
do
  echo "$(timestamp): Processing $hprof_file file..."
  gzip $hprof_file
  aws s3 cp ${hprof_file}.gz "s3://s3-bucket/${ec2InstanceId}_v${BUILD_NUMBER}_${NOW}.gz" --expires $expirationDate
  rm ${hprof_file}.gz
  echo "$(timestamp): upload dump successfuly"
done

echo "$(timestamp): done heap dump loop"