Spring batch jobParameters value null

In a spring batch, I'm trying to pass jobParameters and use them in my JdbcCursorItemReader. A snippet from the same is:

@Configuration
public class SpringBatchConfig extends DefaultBatchConfigurer{

    private String demoVar;

	public String getDemoVar() {
		return demoVar;
	}

	public void setDemoVar(@Value("#{jobParameters['demoVarValue']}") String demoVar) {
		this.demoVar = demoVar;
	}

    @Bean
	@StepScope
	public JdbcCursorItemReader<User> reader1() {
		String sqlQuery = String.format("select * FROM TABLE_NAME where demoVar=? ");
		System.out.println(demoVar);
		JdbcCursorItemReader<User> cursorItemReader = new JdbcCursorItemReader<>();
		cursorItemReader.setDataSource(dataSource);
		cursorItemReader.setSql(sqlQuery);
		cursorItemReader.setPreparedStatementSetter(new PreparedStatementSetter() {
		   public void setValues(PreparedStatement preparedStatement) throws SQLException {
		      preparedStatement.setString(1, demoVar);
		   }
		});
		cursorItemReader.setRowMapper(new DbRowMapper());
		return cursorItemReader;
	}
...

Controller class(containing job launcher):

@RestController
@RequestMapping("/load")
public class LoadController {

    @Autowired
    JobLauncher jobLauncher;

    @Autowired
    Job job;

    @GetMapping("/users")
    public BatchStatus load() throws JobParametersInvalidException, JobExecutionAlreadyRunningException, JobRestartException, JobInstanceAlreadyCompleteException {
        
        JobParameters jobParameters = new JobParametersBuilder()
        							.addString("demoVarValue", "001")
        							.toJobParameters();
        
        JobExecution jobExecution = jobLauncher.run(job, jobParameters);

        System.out.println("JobExecution: " + jobExecution.getStatus());

        return jobExecution.getStatus();
    }
}

But in the reader bean, the value of the demoVar parsed from jobParameters is being passed as null instead of the expected 001.

You don't need the demoVar field (unless you are calling the getter somewhere else). You can pass it as a parameter of reader's bean definition method:

@Bean
@StepScope
public JdbcCursorItemReader<User> reader1(@Value("#{jobParameters['demoVarValue']}") String demoVar) {
    String sqlQuery = String.format("select * FROM TABLE_NAME where demoVar=? ");
    System.out.println(demoVar);
    JdbcCursorItemReader<User> cursorItemReader = new JdbcCursorItemReader<>();
    cursorItemReader.setDataSource(dataSource);
    cursorItemReader.setSql(sqlQuery);
    cursorItemReader.setPreparedStatementSetter(new PreparedStatementSetter() {
       public void setValues(PreparedStatement preparedStatement) throws SQLException {
          preparedStatement.setString(1, demoVar);
       }
    });
    cursorItemReader.setRowMapper(new DbRowMapper());
    return cursorItemReader;
}

Late binding of job parameters is explained in the Late Binding of Job and Step Attributes section of the reference documentation.