Unable to access job parameters in reader/partitioner

I have following configuration for my spring batch partitioner(excluded itemreader and other step details) -

<bean id="myPartitioner" class="com.MyPartitioner" scope="step">
  <property name="param" value="#{jobParameters['myparam']}" />
</bean>

<batch:step id="ReadStep" >
  <batch:tasklet transaction-manager="transactionManager">
    <batch:chunk reader="itemReader"  processor="itemProcessor" writer="mysqlItemWriter" commit-interval="100"/>
  </batch:tasklet>
</batch:step>

<batch:job id="myjob">
  <batch:step id="Step1">
    <batch:partition step="ReadStep" partitioner="myPartitioner">
       <batch:handler grid-size="40" task-executor="taskExecutor"/>
    </batch:partition>
  </batch:step>
</batch:job>

And partitioner code -

public class MyPartitioner implements Partitioner{
        String myparam;

        public void setMyparam(String myparam) {
            this.myparam = myparam;
        }

        public String getMyparam() {
            return myparam;
        }

        @Override
        public Map<String, ExecutionContext> partition(int gridSize)
        {
            System.out.println("JobParam = "+getMyparam());
        }
    }

Quartz job Launcher-

public class SpringBatchJob implements Job{

@Override
public void execute(JobExecutionContext jobExecutionContext) throws JobExecutionException
{
    ApplicationContext applicationContext =new ClassPathXmlApplicationContext("myjob.xml");

    JobLauncher jobLauncher = (JobLauncher) applicationContext.getBean("jobLauncher");
    org.springframework.batch.core.Job job = (org.springframework.batch.core.Job) applicationContext.getBean("jobName");

    JobParameters param = new JobParametersBuilder().addString("myparam", "myparam").addString("time",Long.toString(System.currentTimeMillis())).toJobParameters();

    JobExecution execution = jobLauncher.run(job, param);
}

}

But when the System.out.println executed instead of printing actual jobparameter value I am receiving #{jobParameters['myparam']}. Is there some configuration wrong in here?