Làm sao lấy được phiên bản Java trong thời gian chạy

package org.o7planning.java_14197_version;

public class Main1 {

	public static void main(String[] args) {
		String javaVersion = System.getProperty("java.version");
		System.out.println("Current JVM version: " + javaVersion);
	} 
}

package org.o7planning.java_14197_version;

import java.lang.Runtime.Version;

public class Main2 {

	public static void main(String[] args) {
		Version currentVersion = Runtime.version();
		// Example: 20.0.2+9-78
		System.out.println("Current JVM version: " + currentVersion.toString());
		//
		int feature = currentVersion.feature(); // 20
		int interim = currentVersion.interim(); // 0
		int update = currentVersion.update(); // 2
		int patch = currentVersion.patch(); // 0
		String pre = currentVersion.pre().isPresent() ? currentVersion.pre().get() : "";
		Integer build = currentVersion.build().isPresent() ? currentVersion.build().get() : 0;// 9
		String optional = currentVersion.optional().isPresent() ? currentVersion.optional().get() : ""; // 78
		//
		System.out.println(" - feature: " + feature);
		System.out.println(" - interim: " + interim);
		System.out.println(" - update: " + update);
		System.out.println(" - patch: " + patch);
		System.out.println(" - pre: " + pre);
		System.out.println(" - build: " + build);
		System.out.println(" - optional: " + optional);
		//
		String v17 = "17.0.8+9-LTS";
		Version version17 = Version.parse(v17);
		int value = currentVersion.compareTo(version17);
		if (value == 0) {
			System.out.println("Your Java Version is equal to " + v17);
		} else if (value > 0) {
			System.out.println("Your Java Version is newer than " + v17);
		} else {
			System.out.println("Your Java Version is older than " + v17);
		}
	}
}

package org.o7planning.java_14197_version;

import java.lang.Runtime.Version;

public class ShowVersionInfo {

	public static void main(String[] args) {
		String[] versionStrings = new String[] { //
				"20.0.2+9-78", //
				"17.0.8+9-LTS", //
				"17.0.8.15+9-LTS", //
				"17.0.8.15-X+9-LTS", //
		};

		for (String versionString : versionStrings) {
			Version version = Version.parse(versionString);
			System.out.println("JVM version: " + version.toString());
			//
			int feature = version.feature();
			int interim = version.interim();
			int update = version.update();
			int patch = version.patch();
			String pre = version.pre().isPresent() ? version.pre().get() : "";
			Integer build = version.build().isPresent() ? version.build().get() : 0;
			String optional = version.optional().isPresent() ? version.optional().get() : "";
			//
			System.out.println(" - feature: " + feature);
			System.out.println(" - interim: " + interim);
			System.out.println(" - update: " + update);
			System.out.println(" - patch: " + patch);
			System.out.println(" - pre: " + pre);
			System.out.println(" - build: " + build);
			System.out.println(" - optional: " + optional);
		}
	}
}