Java Runtime getRuntime() Method with Examples

In Java, the Runtime class allows you to interact with the runtime environment of your application. One of the essential methods provided by this class is getRuntime(). This method returns the runtime object associated with the current Java application. With this object, you can access information about the runtime environment, execute system commands, manage processes, and more.

Java Runtime getRuntime() Method

The Runtime.getRuntime() method is a static method that retrieves the runtime object for the current Java application. This object allows you to access various aspects of the application’s runtime environment, such as executing system commands, managing processes, and querying memory usage.

Syntax:

public static Runtime getRuntime()

Example of Java Runtime getRuntime()

Now, let’s explore some practical examples of using the runtime object:

Java

// Java Program to implement
// Java Runtime getRuntime()
import java.io.IOException;

// Driver Class
public class GfgRuntimeExample {
    // main function
    public static void main(String[] args)
    {
        // Getting the runtime object
        Runtime runtime = Runtime.getRuntime();

        // Example 1: Executing System Command
        try {
            // Executing a system command to open a web page
            // (https://www.gfg.com)
            Process process = runtime.exec(
                "xdg-open https://www.gfg.com");

            // Waiting for the process to complete and
            // retrieving the exit code
            int exitCode = process.waitFor();

            // Printing the exit code
            System.out.println(
                "Example 1: Executing System Command");
            System.out.println("Exit Code: " + exitCode);
        }
        catch (IOException | InterruptedException e) {
            e.printStackTrace();
        }

        // Example 2: Retrieving Available Processors
        int processors = runtime.availableProcessors();
        System.out.println(
            "\nExample 2: Retrieving Available Processors");
        System.out.println("Available Processors: "
                           + processors);

        // Example 3: Querying Total and Free Memory
        long totalMemory = runtime.totalMemory();
        long freeMemory = runtime.freeMemory();

        // Converting memory values to megabytes (MB)
        long totalMemoryMB = totalMemory / (1024 * 1024);
        long freeMemoryMB = freeMemory / (1024 * 1024);

        System.out.println(
            "\nExample 3: Querying Total and Free Memory");
        System.out.println("Total Memory (MB): "
                           + totalMemoryMB);
        System.out.println("Free Memory (MB): "
                           + freeMemoryMB);
    }
}

Output:

Example 1: Executing System Command
Exit Code: 0
Example 2: Retrieving Available Processors
Available Processors: 4
Example 3: Querying Total and Free Memory
Total Memory (MB): 123
Free Memory (MB): 78

Conclusion

The Runtime.getRuntime() method provides access to the runtime environment of your Java application. You can use it to execute system commands, manage processes, and retrieve information about system resources like available processors and memory usage.