1. Firstly, reflect back on your past experiences and achievements by going through your resume to sell yourself more effectively.
2. Secondly, understand your prospective employer's requirements and correlate your experiences & achievements so that you can convince your prospective employer as to how you can add value.
3. Thirdly, research the organization you will be interviewing with.
4. Most of the interviewrs start with your resume, and then get into more technical questions. Brush up on the fundamental technical questions. You can find these questions online by googling for "Java interview questions" or I have put together site at
http://www.lulu.com/java-success. Brushing up can give you the much needded confidence in the interviews. Interviews are not just technical contests, it is an opportunity for both parties to assess each other.