Generate a Java thread dump without restarting.

Question

I\'d like to create a thread that keeps track of the memory usage and cpu usage.

If the application reaches a high level, I want to generate an heap dump or a thread

Answer 1

In spring application, we can generate heap dump programmatically by creating cron job.

import com.sun.management.HotSpotDiagnosticMXBean;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;

import javax.management.MBeanServer;
import java.io.File;
import java.lang.management.ManagementFactory;

@Component
public class HeapDumpGenerator {
    @Scheduled(cron = "0 0/5 * * * *")
    public void execute() {
        generateHeapDump();
    }

    private void generateHeapDump() {
        MBeanServer mBeanServer = ManagementFactory.getPlatformMBeanServer();
        String dumpFilePath = System.getProperty("user.home") + File.separator + 
                "heap-dumps" + File.separator +
                "dumpfile_" + System.currentTimeMillis() + ".hprof";
        try {
            HotSpotDiagnosticMXBean hotSpotDiagnosticMXBean = ManagementFactory
                .newPlatformMXBeanProxy(mBeanServer,
                                    "com.sun.management:type=HotSpotDiagnostic", 
                                    HotSpotDiagnosticMXBean.class);
            hotSpotDiagnosticMXBean.dumpHeap(dumpFilePath, Boolean.TRUE);
        } catch (Exception e) {
            // log error
        }
    }
}

It will run at every five minutes, but we can set our own time/interval. We can also add condition before calling generateHeapDump() method.