Java Versions Explained
Java 8 is Java 1.8, where 8 is the version number, and 1.8 is the version string. These versioning names are clarified in Oracle’s article, Java Platform, Standard Edition 8 Names and Versions:
In JDK 8 and JRE 8, the version strings are 1.8 and 1.8.0. Here are some examples where the version string is used:
- java -version (among other information, returns java version “1.8.0”)
- java -fullversion (returns java full version “1.8.0-bxx”)
- javac -source 1.8 (is an alias for javac -source 8)
- java.version system property
- java.vm.version system property
- @since 1.8 tag values
- jdk1.8.0 installation directory
- jre8 installation directory
Oracle periodically makes updates available and, when an update occurs, the version string will also include the update version number. So, JDK 8 update 5, or JDK 8u5, will have the version string “1.8.0_5”. When invoking the java -fullversion command, the result also includes the build number, a level of detail not needed by most users.
The naming convention is explained with additional detail at https://en.wikipedia.org/wiki/Java_version_history.