Below conf works for me:
JAVA_HOME=/JDK1.7.51-64/jdk1.7.0_51/
PATH=/JDK1.7.51-64/jdk1.7.0_51/bin:$PATH
export PATH
export JAVA_HOME
JVM_ARGS="-d64 -Xms1024m -Xmx15360m -server"
/JDK1.7.51-64/jdk1.7.0_51/bin/java $JVM_ARGS -jar `dirname $0`/ApacheJMeter.jar "$@"