private static JRE determineCurrentVersion()

in junit-jupiter-api/src/main/java/org/junit/jupiter/api/condition/JRE.java [121:169]

41 lines of code
13 McCabe index (conditional complexity)


	private static JRE determineCurrentVersion() {
		String javaVersion = System.getProperty("java.version");
		boolean javaVersionIsBlank = StringUtils.isBlank(javaVersion);

		if (javaVersionIsBlank) {
			logger.debug(
				() -> "JVM system property 'java.version' is undefined. It is therefore not possible to detect Java 8.");
		}

		if (!javaVersionIsBlank && javaVersion.startsWith("1.8")) {
			return JAVA_8;
		}

		try {
			// java.lang.Runtime.version() is a static method available on Java 9+
			// that returns an instance of java.lang.Runtime.Version which has the
			// following method: public int major()
			Method versionMethod = Runtime.class.getMethod("version");
			Object version = ReflectionUtils.invokeMethod(versionMethod, null);
			Method majorMethod = version.getClass().getMethod("major");
			int major = (int) ReflectionUtils.invokeMethod(majorMethod, version);
			switch (major) {
				case 9:
					return JAVA_9;
				case 10:
					return JAVA_10;
				case 11:
					return JAVA_11;
				case 12:
					return JAVA_12;
				case 13:
					return JAVA_13;
				case 14:
					return JAVA_14;
				case 15:
					return JAVA_15;
				case 16:
					return JAVA_16;
				default:
					return OTHER;
			}
		}
		catch (Exception ex) {
			logger.debug(ex, () -> "Failed to determine the current JRE version via java.lang.Runtime.Version.");
		}

		// null signals that the current JRE version is "unknown"
		return null;
	}