JMH入门：java.lang.OutOfMemoryError：Java堆空间

Question

My first JMH benchmark code:

package org.sample;

import org.openjdk.jmh.annotations.Benchmark;

public class MyBenchmark {

    @Benchmark
    public void testMethod() {
        // This is a demo/sample template for building your JMH benchmarks. Edit as needed.
        // Put your benchmark code here.
        int i = 100;
        while (i > 0) {
            i--;
        }
    }
}

Running it with any of the following commands results in

java.lang.OutOfMemoryError: Java heap space

on the very first warmup iteration.

java -jar target/benchmarks.jar
java -Xmx256m -jar target/benchmarks.jar
java -Xmx500m -jar target/benchmarks.jar
java -Xmx700m -jar target/benchmarks.jar
java -Xms512m -Xmx1152m -XX:MaxNewSize=256m -jar target/benchmarks.jar

What am I missing?

Answer 1

Because the code I did have was memory intensive (adding a string to itself a hundred times), and I did not rebuild the project before running it again.

Once rebuilt with

mvn clean install

it works fine with the default command/heap size:

java -jar target/benchmarks.jar