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BTrace: A safe, dynamic tracing tool for the Java platform

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
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import org.openjdk.btrace.core.annotations.BTrace;
import org.openjdk.btrace.core.annotations.OnLowMemory;

import java.lang.management.MemoryUsage;

import static org.openjdk.btrace.core.BTraceUtils.println;

/**
 * This sample traces memory threshold exceeds.
 * You need to specify the memory pool to watch
 * out and the usage threshold. You can write
 * script that dumps heap by dumpHeap on crossing
 * the threshold instead of just printing a message.
 * Note that the name of the old gen is dependent on
 * GC algorithm. With ParallelGC, the name is "PS Old Gen".
 */
@BTrace
public class MemAlerter {
    @OnLowMemory(
            pool = "Tenured Gen",
            threshold = 6000000
    )
    public static void onLowMem(MemoryUsage mu) {
        println(mu);
    }
}