[35457] | 1 | class DisplayJavaVersion
|
---|
| 2 | {
|
---|
| 3 | public static void main(String args[])
|
---|
| 4 | {
|
---|
| 5 | boolean verbose = false;
|
---|
| 6 |
|
---|
| 7 | if (args.length == 1) {
|
---|
| 8 | String arg0 = args[0];
|
---|
| 9 |
|
---|
| 10 | if (arg0.equals("-v") || arg0.equals("-verbose") || arg0.equals("--verbose")) {
|
---|
| 11 | verbose = true;
|
---|
| 12 | }
|
---|
| 13 | }
|
---|
| 14 |
|
---|
| 15 | // Adapted from:
|
---|
| 16 | // https://stackoverflow.com/questions/2591083/getting-java-version-at-runtime
|
---|
| 17 |
|
---|
| 18 | String era, major, minor, update, build;
|
---|
| 19 |
|
---|
| 20 | // 'java.version' property returns:
|
---|
| 21 | // era.major.minor
|
---|
| 22 | // 'java.runtime.version' returns:
|
---|
| 23 | // era.major.minor_update-build
|
---|
| 24 |
|
---|
| 25 | // The simpler case can be deal with using:
|
---|
| 26 | // String[] javaVersionElements = System.getProperty("java.version").split("\\.");
|
---|
| 27 | //
|
---|
| 28 | // However, as search4j.cpp has already been written assuming that version information
|
---|
| 29 | // includes update (but not build number) details, then do the following:
|
---|
| 30 | //
|
---|
| 31 | String[] javaVersionElements = System.getProperty("java.runtime.version").split("\\.|_|-b");
|
---|
| 32 |
|
---|
| 33 | era = javaVersionElements[0];
|
---|
| 34 | major = javaVersionElements[1];
|
---|
| 35 | minor = javaVersionElements[2];
|
---|
| 36 | update = javaVersionElements[3];
|
---|
| 37 | build = javaVersionElements[4]; // (unused)
|
---|
| 38 |
|
---|
| 39 |
|
---|
| 40 | // Testing bitness of JVM
|
---|
| 41 | // https://www.baeldung.com/java-detect-jvm-64-or-32-bit
|
---|
| 42 | //boolean is_64bit = com.sun.jna.Platform.is64Bit();
|
---|
| 43 |
|
---|
| 44 | String version_str = era+"."+major+"."+minor+"_"+update;
|
---|
| 45 |
|
---|
| 46 | if (verbose) {
|
---|
| 47 | System.out.println("Version: " + version_str);
|
---|
| 48 | }
|
---|
| 49 | else {
|
---|
| 50 | System.out.println(version_str);
|
---|
| 51 | }
|
---|
| 52 | }
|
---|
| 53 | }
|
---|
| 54 |
|
---|