In preparation for the planned July release of Java 9, Oracle has released guidance for moving applications over to the forthcoming upgrade, which features big changes through modularization.
The newly released JDK (Java Development Kit) 9 Migration Guide notes that every update brings with it binary, source, and behavioral incompatibilities with previous versions. "The modularization of the Java SE Platform brings many benefits but also many changes," Oracle said. "Code that uses only official Java SE Platform APIs and supported JDK-specific APIs should continue to work without change." But code that uses certain features or JDK-internal APIs may not run or may give different results, the company cautioned.