How do I find Java version?

By Wayan in Lang Package 0 Comment

The simplest way to get the Java version is by running the java -version command in your terminal application or Windows command prompt. If Java is installed and available on your path you can get information like below.

java -version                                     
java version "17" 2021-09-14 LTS
Java(TM) SE Runtime Environment (build 17+35-LTS-2724)                       
Java HotSpot(TM) 64-Bit Server VM (build 17+35-LTS-2724, mixed mode, sharing)

Using System Properties

But if you want to get Java version from your Java class or application you can obtain the Java version by calling the System.getProperty() method and provide the property key as argument. Here are some property keys that related to Java version that you can read from the system properties.

package org.kodejava.lang;

public class JavaVersion {
    public static void main(String[] args) {
        String version = System.getProperty("java.version");
        String versionDate = System.getProperty("java.version.date");
        String runtimeVersion = System.getProperty("java.runtime.version");
        String vmVersion = System.getProperty("java.vm.version");
        String classVersion = System.getProperty("java.class.version");
        String specificationVersion = System.getProperty("java.specification.version");
        String vmSpecificationVersion = System.getProperty("java.vm.specification.version");

        System.out.println("java.version: " + version);
        System.out.println("java.version.date: " + versionDate);
        System.out.println("java.runtime.version: " + runtimeVersion);
        System.out.println("java.vm.version: " + vmVersion);
        System.out.println("java.class.version: " + classVersion);
        System.out.println("java.specification.version: " + specificationVersion);
        System.out.println("java.vm.specification.version: " + vmSpecificationVersion);
    }
}

Running the code above give you output like the following:

java.version: 17
java.version.date: 2021-09-14
java.runtime.version: 17+35-LTS-2724
java.vm.version: 17+35-LTS-2724
java.class.version: 61.0
java.specification.version: 17
java.vm.specification.version: 17

Using Runtime.version()

Since JDK 9 we can use Runtime.version() to get Java runtime version. The feature(), interim(), update and patch() methods of the Runtime.Version class are added in JDK 10. These methods is a replacement for the major(), minor() and security() methods of JDK 9.

Below is the code snippet that demonstrate the Runtime.version().

package org.kodejava.lang;

public class RuntimeVersion {
    public static void main(String[] args) {
        System.out.println("Version: " + Runtime.version());
        System.out.println("Feature: " + Runtime.version().feature());
        System.out.println("Interim: " + Runtime.version().interim());
        System.out.println("Update: " + Runtime.version().update());
        System.out.println("Patch: " + Runtime.version().patch());
        System.out.println("Pre: " + Runtime.version().pre().orElse(""));
        System.out.println("Build: " + Runtime.version().build().orElse(null));
        System.out.println("Optional: " + Runtime.version().optional().orElse(""));
    }
}

Running the code snippet above produce the following output:

Version: 17+35-LTS-2724
Feature: 17
Interim: 0
Update: 0
Patch: 0
Pre: 
Build: 35
Optional: LTS-2724

Here are the summary of outputs running the above code using some JDKs installed on my machine.

Version Feature Interim Update Patch Pre Build Optional
10.0.2+13 10 0 2 0 13
11.0.6+8-LTS 11 0 6 0 8 LTS
12.0.2+10 12 0 2 0 10
13.0.2+8 13 0 2 0 8
14+36-1461 14 0 0 0 36 1461
15.0.2+7-27 15 0 2 0 7 27
17+35-LTS-2724 17 0 0 0 35 LTS-2724

How do I get database product information?

By Wayan in JDBC 0 Comment

The code below helps you to get some product information about the database that you use in creating your program. You can retrieve database information such as the major and minor version of the product, the database product name and its release version.

package org.kodejava.jdbc;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.DatabaseMetaData;
import java.sql.SQLException;

public class DatabaseProductInfo {
    private static final String URL = "jdbc:mysql://localhost/kodejava";
    private static final String USERNAME = "kodejava";
    private static final String PASSWORD = "s3cr*t";

    public static void main(String[] args) {
        try (Connection connection =
                     DriverManager.getConnection(URL, USERNAME, PASSWORD)) {
            DatabaseMetaData metadata = connection.getMetaData();

            String productName = metadata.getDatabaseProductName();
            String productVersion = metadata.getDatabaseProductVersion();
            int majorVersion = metadata.getDatabaseMajorVersion();
            int minorVersion = metadata.getDatabaseMinorVersion();

            System.out.println("Product Name    = " + productName);
            System.out.println("Product Version = " + productVersion);
            System.out.println("Major Version   = " + majorVersion);
            System.out.println("Minor Version   = " + minorVersion);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

And here are the results:

Product Name    = MySQL
Product Version = 5.7.43
Major Version   = 5
Minor Version   = 7

Maven Dependencies

<dependency>
    <groupId>com.mysql</groupId>
    <artifactId>mysql-connector-j</artifactId>
    <version>8.1.0</version>
</dependency>

Maven Central

How do I get JDBC driver information?

By Wayan in JDBC 0 Comment 
package org.kodejava.jdbc;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.DatabaseMetaData;
import java.sql.SQLException;

public class JDBCDriverInfo {
    private static final String URL = "jdbc:mysql://localhost/kodejava";
    private static final String USERNAME = "kodejava";
    private static final String PASSWORD = "s3cr*t";

    public static void main(String[] args) {
        try (Connection conn =
                     DriverManager.getConnection(URL, USERNAME, PASSWORD)) {

            DatabaseMetaData metadata = conn.getMetaData();
            String driverName = metadata.getDriverName();
            String driverVersion = metadata.getDriverVersion();
            int majorVersion = metadata.getDriverMajorVersion();
            int minorVersion = metadata.getDriverMinorVersion();

            System.out.println("Driver Name    = " + driverName);
            System.out.println("Driver Version = " + driverVersion);
            System.out.println("Major Version  = " + majorVersion);
            System.out.println("Minor Version  = " + minorVersion);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

The result of our program:

Driver Name    = MySQL Connector/J
Driver Version = mysql-connector-j-8.1.0 (Revision: 7b6f9a337afe6ccb41823df485bf848ca7952b09)
Major Version  = 8
Minor Version  = 1

Maven Dependencies

<dependency>
    <groupId>com.mysql</groupId>
    <artifactId>mysql-connector-j</artifactId>
    <version>8.1.0</version>
</dependency>

Maven Central

How do I get operating system name and version?

By Wayan in Core API, Lang Package 0 Comment 
package org.kodejava.lang;

public class OperatingSystemInfo {
    public static void main(String[] args) {
        // The key for getting operating system name
        String name = "os.name";
        // The key for getting operating system version
        String version = "os.version";
        // The key for getting operating system architecture
        String architecture = "os.arch";

        System.out.println("Name   : " + System.getProperty(name));
        System.out.println("Version: " + System.getProperty(version));
        System.out.println("Arch   : " + System.getProperty(architecture));
    }
}

Below is the example result of our program, of course it could be different from what you’ll see in your machine because it depends on the operating system that you use.

Name   : Windows 10
Version: 10.0
Arch   : amd64

Or

Name   : Mac OS X
Version: 10.12.6
Arch   : x86_64