I have read <a href="https://stackoverflow.com/questions/5103121/how-to-find-the-jvm-version-from-a-program" rel="nofollow">this</a>, but it <em>ain't good enough</em>!
What I mean is: when i run<blockquote>
java version "1.8.0" Java(TM) SE Runtime Environment (build pxa6480sr3fp20-20161019_02(SR3 FP20)) IBM J9 VM (build 2.8, JRE 1.8.0 Linux amd64-64 Compressed References 20161013_322271 (JIT enabled, AOT enabled) J9VM - R28_Java8_SR3_20161013_1635_B322271 JIT - tr.r14.java.green_20161011_125790 GC - R28_Java8_SR3_20161013_1635_B322271_CMPRSS
But when I use any of the programmatic ways to access the JVM version "from within" (as outlined by the question I am linking to), I only see values such as:
Property: java.vm.specification.version : 1.8 Property: java.vm.specification.vendor : Oracle Corporation Property: java.vm.specification.name : Java Virtual Machine Specification Property: java.vm.version : 2.8 Property: java.vm.vendor : IBM Corporation Property: java.vm.name : IBM J9 VM Property: java.specification.version : 1.8 Property: java.specification.vendor : Oracle Corporation Property: java.specification.name : Java Platform API Specification
MX bean --- vmversion: 2.8
My problem: our build server runs a slightly <em>older</em> version of IBM java. java -version would show that, like
J9VM - R28_Java8_SR1_20150410_1531_B243669
But: when I print those system properties, such details are lost! I have not found a way to write java code that would be able to distinguish that slightly older JVM from the newer one.
Long story short: is there any programmatic way to do something "within my JVM" that would give me that level of detail?
(basically I need that to dynamically disable some of our JUnit tests; they simply dont work with the older JVM; but I want them to be executed when running in my local eclipse installation with a newer JVM)Answer1:
I don't have IBM Java, only Oracle Java. When I do
java -version I get:
java version "1.8.0_91" Java(TM) SE Runtime Environment (build 1.8.0_91-b14) Java HotSpot(TM) 64-Bit Server VM (build 25.91-b14, mixed mode)
I can reproduce that exact output with this code:
System.out.printf("java version \"%s\"%n" + "%s (build %s)%n" + "%s (build %s, %s)%n", System.getProperty("java.version"), System.getProperty("java.runtime.name"), System.getProperty("java.runtime.version"), System.getProperty("java.vm.name"), System.getProperty("java.vm.version"), System.getProperty("java.vm.info"));
There might be other information added by IBM Java. Why not try dumping all system properties and see for yourself:
new TreeMap<>(System.getProperties()).entrySet().forEach(e -> System.out.printf("%s = %s%n", e.getKey(), e.getValue()) );