Amazon DyanamoDB ,Using filter expressions with scan operations in Java

I am trying to get all the items whose price is greater than a certain value,but not able to use the filter expressions correctly.

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

import com.amazonaws.auth.profile.ProfileCredentialsProvider;
import com.amazonaws.regions.Region;
import com.amazonaws.regions.Regions;
import com.amazonaws.services.dynamodbv2.AmazonDynamoDBClient;
import com.amazonaws.services.dynamodbv2.document.DynamoDB;
import com.amazonaws.services.dynamodbv2.document.Item;
import com.amazonaws.services.dynamodbv2.document.ItemCollection;
import com.amazonaws.services.dynamodbv2.document.QueryOutcome;
import com.amazonaws.services.dynamodbv2.document.Table;
import com.amazonaws.services.dynamodbv2.document.spec.QuerySpec;
import com.amazonaws.services.dynamodbv2.model.AttributeValue;
import com.amazonaws.services.dynamodbv2.model.PutItemRequest;
import com.amazonaws.services.dynamodbv2.model.ScanRequest;
import com.amazonaws.services.dynamodbv2.model.ScanResult;

public class QuerySample {
    // Setting up the client

    static AmazonDynamoDBClient db = new AmazonDynamoDBClient(
            new ProfileCredentialsProvider());
    // Setting up the DB
    static DynamoDB dynamoDB = new DynamoDB(db);

    public static void main(String a[]) {
        // Setting up the Region
        Region usWest = Region.getRegion(Regions.US_WEST_2);
        db.setRegion(usWest);
        Table table = dynamoDB.getTable("Thread");
        SimpleDateFormat dt = new SimpleDateFormat("yyyy-mm-dd HH:mm:ss.SSS");
        long time = (new Date()).getTime();
        Date date = new Date();
        date.setTime(time);
        System.out.println("The date is " + date);
        // ScanRequest scanRequest = new ScanRequest()
        // .withTableName("sys_ping");
        // ScanResult result = db.scan(scanRequest);
        // for (Map<String, AttributeValue> item : result.getItems()){
        // System.out.println(item);
        // }

        Map<String, Object> expressionAttributeValues = new HashMap<String, Object>();
        expressionAttributeValues.put(":val", "19");
        expressionAttributeValues.put(":val1",
                new AttributeValue().withN("2000"));
        ScanRequest scanRequest = new ScanRequest().withTableName(
                "ProductCatalog").withFilterExpression("Price >= :val");
        ScanResult result = db.scan(scanRequest);
        for (Map<String, AttributeValue> item : result.getItems()) {
            System.out.println(item);

        }

    }
}

It throws the following runtime exception

Exception in thread "main" com.amazonaws.AmazonServiceException: Invalid FilterExpression: An expression attribute value used in expression is not defined; attribute value: :val (Service: AmazonDynamoDBv2; Status Code: 400; Error Code: ValidationException; Request ID: FEQBP55SPJIT60JVFPVO6N6BLBVV4KQNSO5AEMVJF66Q9ASUAAJG)

You are misusing the API. Look at Map<String, Object> expressionAttributeValues

1. There is both :val and :val1 there.
2. You are not passing it to the new ScanRequest()