How to know about OutOfMemory or StackOverflow errors ahead of time

Question

In Java, is there a way to know that a StackOverflow error or OutOfMemory exception may happen soon?

The OutOfMemory exception m

Answer 1

Implementation example using MemoryPoolMXBean

import static java.lang.management.ManagementFactory.getMemoryMXBean;
import static java.lang.management.ManagementFactory.getMemoryPoolMXBeans;
import static java.lang.management.MemoryNotificationInfo.MEMORY_THRESHOLD_EXCEEDED;
import static java.lang.management.MemoryType.HEAP;
import java.lang.management.MemoryPoolMXBean;
import java.lang.management.MemoryUsage;
import java.util.Collection;
import java.util.concurrent.CopyOnWriteArrayList;
import javax.management.Notification;
import javax.management.NotificationEmitter;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class MemoryWatcher {

    public interface Listener {
        void memoryUsageLow(long usedMemory, long maxMemory);
    }

    private static final MemoryPoolMXBean tenuredGenPool = findTenuredGenPool();
    private static final Logger logger = LoggerFactory.getLogger(MemoryWatcher.class);

    private static MemoryPoolMXBean findTenuredGenPool() {
        for (MemoryPoolMXBean pool : getMemoryPoolMXBeans())
            if (pool.getType() == HEAP && pool.isUsageThresholdSupported())
                return pool;
        return null;
    }

    public static MemoryPoolMXBean getTenuredGenPool() {
        return tenuredGenPool;
    }

    private final Collection listeners = new CopyOnWriteArrayList<>();

    public MemoryWatcher(double usageThresholdPercent) {
        if (tenuredGenPool == null) {
            logger.warn("Tenured pool is not used");
            return;
        }
        if (tenuredGenPool.getUsageThreshold() != 0)
            logger.warn("Overriding tenured usage threshold {} with {}", tenuredGenPool.getUsage().getMax() / (double) tenuredGenPool.getUsageThreshold(), usageThresholdPercent);
        tenuredGenPool.setUsageThreshold((long) (tenuredGenPool.getUsage().getMax() * usageThresholdPercent));

        NotificationEmitter emitter = (NotificationEmitter) getMemoryMXBean();
        emitter.addNotificationListener((Notification n, Object hb) -> {
            MemoryUsage usage = tenuredGenPool.getUsage();
            if (n.getType().equals(MEMORY_THRESHOLD_EXCEEDED) && usage.getMax() == usage.getCommitted())
                listeners.forEach(listener -> listener.memoryUsageLow(usage.getUsed(), usage.getMax()));
        }, null, null);
    }

    public boolean addListener(Listener listener) {
        return listeners.add(listener);
    }

    public boolean removeListener(Listener listener) {
        return listeners.remove(listener);
    }
}