Oracle introduced Java SE 8 Upgrade exam and very soon there will be OCPJP 8 beta exam to cover all new changes.

What are the changes introduced in Java SE 8?

Lambda Expressions, a new language feature introduced in Java SE 8. These expressions treat functionality as a method argument, or code as data. Lambda expressions let you express instances of single-method interfaces (referred to as functional interfaces) more compactly.

Method references using lambda expressions.

Default methods for interfaces.

Annotation Changes
Repeating Annotations. We can apply the same annotation type more than once to the same declaration or type use.
Type Annotations. We can have ability to apply an annotation anywhere a type is used, not just on a declaration. This feature enables improved type checking of your code.

Collection improvements. The classes in the new java.util.stream package can be integrated into the Collections API, which enables bulk operations on collections, such as sequential or parallel map-reduce transformations. Performance Improvement for HashMaps with Key Collisions

For internationalization Java SE 8 supports Unicode 6.2.0 and adoption of Unicode CLDR Data and the java.locale.providers System Property.
New Calendar and Locale APIs. Java SE 8 introduced new Date/Time API.

The NIO introduced new SelectorProvider implementation for Solaris based on the Solaris event port mechanism. Performance improvement for the java.lang.String(byte[], *) constructor and the java.lang.String.getBytes() method.

New changes in util package. Parallel Array Sorting, standard encoding and decoding Base64 and unsigned arithmetic support.

Changes in JDBC: The JDBC-ODBC Bridge has been removed and JDBC 4.2 introduces new features.

The following changes are part of java.util.concurrent package.

• Classes and interfaces have been added
• Methods have been added to the java.util.concurrent.ConcurrentHashMap class to support aggregate operations based on the newly added streams facility and lambda expressions.
• Classes have been added to the java.util.concurrent.atomic package to support scalable updatable variables.
• The java.util.concurrent.locks.StampedLock class has been added to provide a capability-based lock with three modes for controlling read/write access.

What additional topics we can expect for OCPJP 8 exam?
We can expect all new topics except networking API changes and security changes as part of core Java.

You can keep watch our OCPJP 8 Training Lab page about the changes of Java 8 Certification at http://www.epractizelabs.com/certification/oracle/ocpjp-8/mockexam.html