How to know JDK version from within Java code

Question

How to know JDK version from within Java code

Answer 1

I presume you mean just the Java version, in which case try this:

String version = System.getProperty("java.version"); 

Answer 2

Relying on the java.version string for anything else than showing to a human is fragile and will break if running on another Java implementation.

The only reliable way programatically is to use reflection to carefully ask if a given facility is available, and then select the appropriate code accordingly.