Not able to load credentials of an EC2 instance on InstanceProfileCredentialsProvider

I have attached an EC2 role to the instance , to my EC2 instance and I am running my AWS JAVA SDK . When I am trying to load the credentials this way :

InstanceProfileCredentialsProvider instanceCred = new InstanceProfileCredentialsProvider();

I am getting the following error :

Exception in thread "main" com.amazonaws.AmazonClientException: Unable to load credentials.
    at com.amazonaws.auth.InstanceProfileCredentialsProvider.loadCredentials(InstanceProfileCredentialsProvider.java:195)
    at com.amazonaws.auth.InstanceProfileCredentialsProvider.getCredentials(InstanceProfileCredentialsProvider.java:124)

Can any suggest what problem I might be making ?