Java 9 (next)
New Java version is under development. Preliminary JDK versions and information can be found at https://jdk9.java.net/
Java 9 general availability is planned for September 2016.
Java 8 (current)
Java 8 is the current Java version.
Java 8 JDK/JRE update 65/66 (8u65/8u66) has been released. In addition to several fixes, this release does include additional currencies (fund codes) support. Release 66 bug fixes set is bigger.
Complete release notes can be found here.
JDK 8 can be downloaded here.
Java 7 (end-of-life)
Java 7 79/80 is the last public release. Updates are available for Oracle commercial customers only.
JDK 7u80 can be downloaded from Java 7 Archive downloads.
Java 6 (end-of-life)
Java 6 45 is the last public release. Updates are available for Oracle commercial customers only.
JDK 6u45 can be downloaded from Java 6 Archive downloads.