CODEWITHSUNDEEP
javamemorymemory-management
Maria
Maria

Reputation: 604

Available memory in Machine

Is there any way I could find out available or free ram in machine using Java ?

Need this detail so that I could launch my JVM accordingly.

Upvotes: 0

Views: 218

Answers (1)

Holger
Holger

Reputation: 298529

There is an API allowing to get the numbers, but it’s not part of the official API in Java 8 and depends on an optional module, jdk.management, in JDK 11.

You can use dynamic access to avoid direct code dependencies to unofficial APIs. In the common implementations, i.e. OpenJDK and Oracle’s JDK distribution, it will be available:

import java.lang.management.ManagementFactory;
import javax.management.*;

public class Memory {
    public static void main(String[] args) throws JMException {
        MBeanServer mBeanServer = ManagementFactory.getPlatformMBeanServer();
        ObjectName objectName = new ObjectName("java.lang:type=OperatingSystem");

        Long free = (Long)mBeanServer.getAttribute(objectName, "FreePhysicalMemorySize");
        Long total= (Long)mBeanServer.getAttribute(objectName, "TotalPhysicalMemorySize");

        final double gb = 0x1p-30;

        System.out.printf("%.2f GB of %.2f GB free%n", free * gb, total * gb);

        total = (Long)mBeanServer.getAttribute(objectName, "TotalSwapSpaceSize");
        free  = (Long)mBeanServer.getAttribute(objectName, "FreeSwapSpaceSize");

        System.out.printf("%.2f GB of %.2f GB swap free%n", free * gb, total * gb);
    }
}

Upvotes: 2

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