Amazon web services-running EC2 instance via java program using AWS APIs

[arushi tomar]

I am new to java programming and I have been trying to start an aws EC2 instance using a java program that i have written using help from various websites, but I can't seem to succeed after 2 days of trying.

here is my java code

public class StartInstancesRequest extends Amamzon WebServiceRequest
      implements java.io.Serializable,java.lang.Cloneable,
      DryRunSupportedRequest<StartInstancesRequest>{

private static final long serialVersionUID = 1L;
private static ClientConfiguration credentials;

@Override
public Request<StartInstancesRequest> getDryRunRequest() {


            return null;
}   
  public static void main(String[] args)
  {
      AmazonEC2Client ec2 = new AmazonEC2Client(credentials); 
        RunInstancesRequest runInstancesRequest = new RunInstancesRequest();

              runInstancesRequest.withImageId("ami-96f1c1c4")
                                 .withInstanceType("t2.micro")
                                 .withMinCount(1)
                                 .withMaxCount(1)
                                 .withKeyName("development")
                                 .withSecurityGroups("DevelopmentTesting");

              RunInstancesResult res = ec2.runInstances(runInstancesRequest); 
              System.out.println(res.toString());
              return;
  }
public static ClientConfiguration getCredentials() {
    return credentials;
}
public static void setCredentials(ClientConfiguration credentials) {
    StartInstancesRequest.credentials = credentials;
}
  }

and when i run the program i get this in my console

Exception in thread "main" java.lang.NullPointerException at com.amazonaws.http.HttpClientFactory.createHttpClient(HttpClientFactory.java:92) at com.amazonaws.http.AmazonHttpClient.(AmazonHttpClient.java:200) at com.amazonaws.AmazonWebServiceClient.(AmazonWebServiceClient.java:129) at com.amazonaws.services.ec2.AmazonEC2Client.(AmazonEC2Client.java:196) at com.amazonaws.services.ec2.AmazonEC2Client.(AmazonEC2Client.java:173) at com.amazonaws.services.ec2.AmazonEC2Client.(AmazonEC2Client.java:101) at com.amazonaws.services.ec2.model.StartInstancesRequest.main(StartInstancesRequest.java:25)

Can anyone help me? Am I writing the code right??

[Rodion Gork]

AmazonEC2Client ec2 = new AmazonEC2Client(credentials);

Am I right supposing that "credentials" here are null - it looks like you never initialize them?

[Campbell Ritchie]

You have probably not come across the code button yet. Always use it: i edited your post with it and had to break some long lines and doesn't it look better . Please always use copy‑and‑paste for code; you appear to have a compiler error in line 1 and I think you have divided the name of a class in two by mistake. Don't say java.lang.Anything (normally); simply use the class name, and make sure you don't have any classes in your package with the same name as a java.lang class.

Go through books like Effective Java™ by Joshua Bloch and you find warnings against retuning null (page 201). I saw that (line 12) and thought, “He is going to get a Null Exception,”

[arushi tomar]

Thank you for the replies. The issue is now resolved.