According to the submission materials, here's what Oracle intends to improve upon in the Java 7:
Continually improving the productivity of Java developers is critical to keeping the Java SE platform at the forefront of software development.
Exploiting the opportunities of multicore CPUs in a way that is safe and practical for developers is essential for all Java applications.
With the advent of new programming languages on the JVM it is important for the JVM to reflect the needs of language implementors, and that the Java language be able to interoperate with those languages.
In order to provide a competitive user experience Java applications sometimes need the ability to access and manipulate, in a controlled and testable fashion, the native semantics of the file system of the underlying platform.
And, also from submission materials, here's what it intends to improve in Java 8:
Exploiting the opportunities of multi-core CPUs in a way that is safe and practical for programmers is essential for all Java applications.
Modularity is a fundamental building block for developing, deploying, managing, and evolving all Java applications. Existing frameworks and tools support these tasks today, but standardization in the Java SE Platform would promote interoperability and benefit developers, users, and vendors.