How do I get peak live threads count?

By Wayan in Core API, Management 0 Comment 
package org.kodejava.lang.management;

import java.lang.management.ManagementFactory;
import java.lang.management.ThreadMXBean;

public class PeakThreadCount {
    public static void main(String[] args) {
        // Get the managed bean for the thread system of the Java
        // virtual machine.
        ThreadMXBean bean = ManagementFactory.getThreadMXBean();

        // Get the peak live thread count since the Java virtual
        // machine started or peak was reset.
        int peakThreadCount = bean.getPeakThreadCount();
        System.out.println("Peak Thread Count = " + peakThreadCount);
    }
}

How do I get current number of live threads?

By Wayan in Core API, Management 0 Comment 
package org.kodejava.lang.management;

import java.lang.management.ManagementFactory;
import java.lang.management.ThreadMXBean;

public class ThreadCount {

    public static void main(String[] args) {
        // Get the managed bean for the thread system of the Java
        // virtual machine.
        ThreadMXBean bean = ManagementFactory.getThreadMXBean();

        // Get the current number of live threads including both
        // daemon and non-daemon threads.
        int threadCount = bean.getThreadCount();
        System.out.println("Thread Count = " + threadCount);
    }
}

How do I get the Java classpath?

By Wayan in Core API, Management 0 Comment

The RuntimeMXBean.getClassPath() returns the Java class path that is used by the system class loader to search for class files. This method is equivalent to System.getProperty("java.class.path").

Multiple paths in the Java class path are separated by the path separator character of the platform of the Java virtual machine being monitored.

package org.kodejava.lang.management;

import java.lang.management.ManagementFactory;
import java.lang.management.RuntimeMXBean;

public class GetClassPath {
    public static void main(String[] args) {
        RuntimeMXBean bean = ManagementFactory.getRuntimeMXBean();
        String classPath = bean.getClassPath();
        System.out.println("ClassPath = " + classPath);
    }
}

How do I get system properties information?

By Wayan in Core API, Management 0 Comment 
package org.kodejava.lang.management;

import java.lang.management.ManagementFactory;
import java.lang.management.RuntimeMXBean;
import java.util.Map;
import java.util.Set;

public class GetSystemProperties {
    public static void main(String[] args) {
        RuntimeMXBean bean = ManagementFactory.getRuntimeMXBean();

        // Returns a map of names and values of all system
        // properties. This method calls System.getProperties()
        // to get all system properties. Properties whose
        // name or value is not a String are omitted.
        Map<String, String> systemProperties = bean.getSystemProperties();
        Set<String> keys = systemProperties.keySet();
        for (String key : keys) {
            String value = systemProperties.get(key);
            System.out.printf("Property[%s] = %s%n", key, value);
        }
    }
}

Some properties produced by the code snippet above are:

Property[java.specification.version] = 17
Property[sun.cpu.isalist] = amd64
Property[sun.jnu.encoding] = Cp1252
Property[java.vm.vendor] = Oracle Corporation
Property[sun.arch.data.model] = 64
Property[user.variant] = 
Property[java.vendor.url] = https://java.oracle.com/
...
...
Property[java.vm.info] = mixed mode, sharing.
Property[java.vendor] = Oracle Corporation.
Property[java.vm.version] = 17+35-LTS-2724.
Property[sun.io.unicode.encoding] = UnicodeLittle.
Property[java.class.version] = 61.0.

How do I get the start time of a JVM?

By Wayan in Core API, Management 0 Comment 
package org.kodejava.lang.management;

import java.lang.management.ManagementFactory;
import java.lang.management.RuntimeMXBean;
import java.util.Date;

public class GetStartTime {
    public static void main(String[] args) {
        RuntimeMXBean bean = ManagementFactory.getRuntimeMXBean();

        // Returns the start time of the Java virtual machine in 
        // milliseconds. This method returns the approximate time 
        // when the Java virtual machine started.
        long startTime = bean.getStartTime();
        Date startDate = new Date(startTime);
        System.out.println("Start Time = " + startTime);
        System.out.println("Start Date = " + startDate);
    }
}

The result of the code snippet above:

Start Time = 1634391703196
Start Date = Sat Oct 16 21:41:43 CST 2021