To set up aws functionality in your existing java code first of all you need a aws-sdk jar file so it depends on project if a project is mavenize then add a dependency in pom.xml file
otherwise download aws-java-sdk jar file from Download link.
To access any AWS account you need access key and secret key
so first step is create BasicAWSCredentials object and pass access key and secret key and then depends on create object of any service EC2
Same way you can access any of the AWS service like RDS, ELB, EBS, RedShift, CloudWatch
So now you have a result of aws so whatever you are seeing in amazon console everything you can do by using this amazon sdk.
otherwise download aws-java-sdk jar file from Download link.
To access any AWS account you need access key and secret key
so first step is create BasicAWSCredentials object and pass access key and secret key and then depends on create object of any service EC2
Same way you can access any of the AWS service like RDS, ELB, EBS, RedShift, CloudWatch
So now you have a result of aws so whatever you are seeing in amazon console everything you can do by using this amazon sdk.