Reputation: 18035
How to find the JVM version from a program?
I want to write a sample Java file in which I want to know the JVM version in which the class is running. Is there a way?
Upvotes: 152
Views: 150142
Answers (11)
Reputation: 61
System.getProperty("sun.arch.data.model");
Java 32 Bit and 64 Bit Control
Integer vers = Integer.parseInt(System.getProperty("java.version").split("\\.")[1]);
String bitMode = System.getProperty("sun.arch.data.model").toString();
System.out.println(vers);
System.out.println(bitMode);
Output:
6
32
Upvotes: 0
Reputation: 842
we can use the JVM runtime's class bytecode version to check against required JVM release:
This solution doesn't depend on any Enum constants etc and is backward compatible.
NOTE: This solution works irrespective of the bytecode version of the current executing class or other classes/jars in runtime classpath because the property reflects the assigned bytecode version for a given JDK release.
example: if a class is compiled at sourceCompatibility/targetCompatiblity 1.8/release level 8, but if it is executed using Java 11 JDK/runtime, then the java.class.version system property value will still be 55(Java11) though the executing class bytecode level is 52(Java8).
public class Java9Check{
public static void main(String[] args){
String bytecodeStr = System.getProperty("java.class.version");
try {
double bytecodeVal = Double.parseDouble(bytecodeStr);
int bytecode = (int) bytecodeVal;
// if Java 8 or below, return ExitCode(1)
if (bytecode < 53) {
System.out.println("Java8 or below");
System.exit(1);
}
System.out.println("Java9 or above");
} catch (NumberFormatException ignored) {}
// proceed with normal exit, ExitCode(0)
}
}
JDK Version Class File Version
Java 1.0 45.0
Java 1.1 45.3
Java 1.2 46.0
Java 1.3 47.0
Java 1.4 48.0
Java 5 49.0
Java 6 50.0
Java 7 51.0
Java 8 52.0
Java 9 53.0
Java 10 54.0
Java 11 55.0
Java 12 56.0
Java 13 57.0
Java 14 58.0
Java 15 59.0
Java 16 60.0
Java 17 61.0
Java 18 62.0
Java 19 63.0
Java 20 64.0
Java 21 65.0
Java 22 66.0
Upvotes: 1
Reputation: 4554
Since Java 9 we have a new static method: Runtime.version().
The object returned has interesting methods such as feature() or compareToIgnoreOptional() what might be easier to work with (e.g. Runtime.version().feature() >= 11).
Upvotes: 2
Reputation: 168795
It seems the java.specification.version is the best one for the job.
E.G.
java.specification.version 1.6
java.version 1.6.0_23
java.vm.version 19.0-b09
java.runtime.version 1.6.0_23-b05
Upvotes: 61
Reputation: 298818
Use:
System.getProperty("java.version");
Where java.version can be replaced with one of the many other system properties related to the current Java version. Here is a table of them:
Property Value (OpenJDK 12) Value (Oracle JRE 8u201) Value (Sun JRE 5u22) Description
------------------------------- ----------------------------------------- --------------------------------------- ---------------------------------------------------- ---------------------------------------------------------------------------------------------------------------
java.version "12" "1.8.0_201" "1.5.0_22" Java Runtime Environment version, which may be interpreted as a Runtime.Version
java.version.date "2019-03-19" null null Java Runtime Environment version date, in ISO-8601 YYYY-MM-DD format, which may be interpreted as a LocalDate
java.vendor "Oracle Corporation" "Oracle Corporation" "Sun Microsystems Inc." Java Runtime Environment vendor
java.vendor.version null null null Java vendor version
java.vendor.url "https://java.oracle.com/" "http://java.oracle.com/" "http://java.sun.com/" Java vendor URL
java.vendor.url.bug "https://bugreport.java.com/bugreport/" "http://bugreport.sun.com/bugreport/" "http://java.sun.com/cgi-bin/bugreport.cgi" Undocumented
java.specification.name "Java Platform API Specification" "Java Platform API Specification" "Java Platform API Specification" Java Runtime Environment specification name
java.specification.vendor "Oracle Corporation" "Oracle Corporation" "Sun Microsystems Inc." Java Runtime Environment specification vendor
java.specification.version "12" "1.8" "1.5" Java Runtime Environment specification version, whose value is the feature element of the runtime version
java.vm.name "OpenJDK 64-Bit Server VM" "Java HotSpot(TM) 64-Bit Server VM" "Java HotSpot(TM) 64-Bit Server VM" Java Virtual Machine implementation name
java.vm.vendor "Oracle Corporation" "Oracle Corporation" "Sun Microsystems Inc." Java Virtual Machine implementation vendor
java.vm.version "12+33" "25.201-b09" "1.5.0_22-b03" Java Virtual Machine implementation version which may be interpreted as a Runtime.Version
java.vm.info "mixed mode, sharing" "mixed mode" "mixed mode" Undocumented
java.vm.specification.name "Java Virtual Machine Specification" "Java Virtual Machine Specification" "Java Virtual Machine Specification" Java Virtual Machine specification name
java.vm.specification.vendor "Oracle Corporation" "Oracle Corporation" "Sun Microsystems Inc." Java Virtual Machine specification vendor
java.vm.specification.version "12" "1.8" "1.0" Java Virtual Machine specification version, whose value is the feature element of the runtime version
java.runtime.name "OpenJDK Runtime Environment" "Java(TM) SE Runtime Environment" "Java(TM) 2 Runtime Environment, Standard Edition" Undocumented
java.runtime.version "12+33" "1.8.0_201-b09" "1.5.0_22-b03" Undocumented
java.class.version "56.0" "52.0" "49.0" Java class format version number
jdk.debug "release" null null Undocumented
sun.java.launcher "SUN_STANDARD" "SUN_STANDARD" "SUN_STANDARD" Undocumented
sun.management.compiler "HotSpot 64-Bit Tiered Compilers" "HotSpot 64-Bit Tiered Compilers" "HotSpot 64-Bit Server Compiler" Undocumented
Sources:
- Output of
java -XshowSettings:all -versionfor a variety of JVM versions. - Java API Reference documentation for
System.getProperties()
Upvotes: 100
Reputation: 20891
Just simply call,
System.out.println(System.getProperty("java.specification.version"));
System.out.println(System.getProperty("java.runtime.version"));
Example output:
9
9+176
Upvotes: 5
Reputation: 140407
Depending on what one needs, the other answers can help.
In my case, they didn't. I was looking for the "fully qualified" version information of a IBM JDK.
So, the "real" answer can be: just dump all system properties and check if there is one that gives you what you are looking for.
In my case; I found that the IBM JDK knows a
Property: java.fullversion
JRE 1.8.0 IBM J9 2.8 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 J9CL - 20161013_322271
Upvotes: 2
Reputation:
Below java code returns JVM versions which are available in your current IDE
List<VirtualMachineDescriptor> descriptors = VirtualMachine.list();
for (VirtualMachineDescriptor descriptor : descriptors) {
System.out.println("Found JVM: " + descriptor.displayName());
try {
VirtualMachine vm = VirtualMachine.attach(descriptor);
String version = vm.getSystemProperties().getProperty("java.runtime.version");
System.out.println(" Runtime Version: " + version);
String connectorAddress = vm.getAgentProperties().getProperty("com.sun.management.jmxremote.localConnectorAddress");
if (connectorAddress == null) {
connectorAddress = vm.getAgentProperties().getProperty("com.sun.management.jmxremote.localConnectorAddress");
}
JMXServiceURL url = new JMXServiceURL(connectorAddress);
JMXConnector connector = JMXConnectorFactory.connect(url);
MBeanServerConnection mbs = connector.getMBeanServerConnection();
ObjectName threadName = new ObjectName(ManagementFactory.THREAD_MXBEAN_NAME);
Integer threadCount = (Integer)mbs.getAttribute(threadName, "ThreadCount");
System.out.println(" Thread count: " + threadCount);
}
catch (Exception e) {
// ...
}
output:
Found JVM: /home/.../STS IDE/sts-bundle/sts-3.7.2.RELEASE//plugins/org.eclipse.equinox.launcher_1.3.100.v20150511-1540.jar -os linux -ws gtk -arch x86_64 -showsplash -launcher /home/.../STS IDE/sts-bundle/sts-3.7.2.RELEASE/STS -name STS --launcher.library /home/.../STS IDE/sts-bundle/sts-3.7.2.RELEASE//plugins/org.eclipse.equinox.launcher.gtk.linux.x86_64_1.1.300.v20150602-1417/eclipse_1612.so -startup /home/.../STS IDE/sts-bundle/sts-3.7.2.RELEASE//plugins/org.eclipse.equinox.launcher_1.3.100.v20150511-1540.jar --launcher.overrideVmargs -exitdata 1ad000f -product org.springsource.sts.ide -vm /usr/bin/java -vmargs -Dosgi.requiredJavaVersion=1.7 -Xms40m -XX:MaxPermSize=256m -Xverify:none -Xmx1200m -jar /home/.../STS IDE/sts-bundle/sts-3.7.2.RELEASE//plugins/org.eclipse.equinox.launcher_1.3.100.v20150511-1540.jar
Runtime Version: 1.8.0_91-b14
Found JVM: com.intellij.idea.Main
Runtime Version: 1.8.0_91-b14
Found JVM: Test
Runtime Version: 1.7.0_80-b15
Upvotes: 2
Reputation: 51
Information about versions is stored as a properties of System class.
http://docs.oracle.com/javase/6/docs/api/java/lang/System.html#getProperties%28%29
Upvotes: 0
Reputation: 115328
System.getProperty("java.version") returns what you need.
You can also use JMX if you want:
ManagementFactory.getRuntimeMXBean().getVmVersion()
Upvotes: 159
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