JMockit does not work with newest versions of JaCoCo plugin

[pksilen]

• JDK: 17
• JMockit Version number: 1.49

Some unit tests throw ArrayIndexOutOfBoundsException when using
newest version 0.8.11 of the JaCoCo plugin. An older version of JaCoCo plugin like 0.8.3 works ok.

The expection is thrown in a test case where I mock a singleton class. If I remove the mocking the test case works ok.

Mocking of the below class in a test case field using the @mocked annotation cause all test cases in the module to fail with
the ArrayIndexOutOfBoundsException :

package com.nokia.cni.exportica.batchwriter.common.metrics;

import com.nokia.cni.exportica.batchwriter.application.config.ApplicationConfig;
import com.nokia.cni.exportica.batchwriter.common.configproperties.ConfigProperties;
import com.nokia.cni.exportica.batchwriter.common.metrics.counter.CounterDescriptions;
import com.nokia.cni.exportica.batchwriter.common.metrics.counter.CounterKey;
import com.nokia.cni.exportica.batchwriter.common.metrics.counter.CounterNames;
import com.nokia.cni.exportica.batchwriter.common.metrics.gauge.GaugeDescriptions;
import com.nokia.cni.exportica.batchwriter.common.metrics.gauge.GaugeKey;
import com.nokia.cni.exportica.batchwriter.common.metrics.gauge.GaugeNames;
import com.nokia.cni.exportica.batchwriter.common.metrics.label.LabelKey;
import com.nokia.cni.exportica.batchwriter.common.metrics.label.LabelNames;
import com.nokia.cni.exportica.batchwriter.messagequeue.MessageQueueConfig;
import com.nokia.cni.exportica.batchwriter.output.file.writer.config.FileWriterConfig;
import io.prometheus.client.Counter;
import io.prometheus.client.Gauge;

import java.util.*;

@SuppressWarnings("UseOfConcreteClass")
public final class Metrics {
    private static Metrics instance;
    final Map<CounterKey, Counter> keyToCounter = new EnumMap<>(CounterKey.class);
    final Map<GaugeKey, Gauge> keyToGauge = new EnumMap<>(GaugeKey.class);
    private final double msgQueueMaxLength;
    private final String productName;
    private final String useCaseName;
    private final String podName;
    private final String outputType;

    public static void createInstance(final ConfigProperties configProperties) {
        if (instance == null) {
            instance = new Metrics(configProperties);
        }
    }

    public static Metrics getInstance() {
        return instance;
    }

    @SuppressWarnings("LawOfDemeter")
    private Metrics(final ConfigProperties configProperties) {
        final var namesConfig = new ApplicationConfig(configProperties).namesConfig;
        productName = namesConfig.productName;
        useCaseName = namesConfig.useCaseName;
        podName = namesConfig.podName;
        outputType = new FileWriterConfig(configProperties).destType;
        msgQueueMaxLength = new MessageQueueConfig(configProperties).maxLength;
        createCounters();
        createGauges();
    }

    public void incrementCounter(final CounterKey key, final long value, final String kafkaTopic) {
        final var counter = keyToCounter.get(key);
        counter.labels(getLabelValues(kafkaTopic)).inc(value);
    }

    public void updateMsgQueueGauges(final int msgQueueLength) {
        keyToGauge.get(GaugeKey.MESSAGE_QUEUE_LENGTH).labels(getLabelValues("")).set(msgQueueLength);
        keyToGauge.get(GaugeKey.MESSAGE_QUEUE_UTILIZATION).labels(getLabelValues("")).set(msgQueueLength / msgQueueMaxLength);
    }

    private void createCounters() {
        Arrays.stream(CounterKey.values()).forEach(counterKey -> keyToCounter.put(counterKey, createCounter(counterKey)));
    }

    private Counter createCounter(final CounterKey counterKey) {
        return Counter.build()
                .name(createProductNamespacedMetricName(CounterNames.get(counterKey)))
                .help(CounterDescriptions.get(counterKey))
                .labelNames(getLabelNames())
                .register();
    }

    private void createGauges() {
        Arrays.stream(GaugeKey.values()).forEach(gaugeKey -> keyToGauge.put(gaugeKey, createGauge(gaugeKey)));
    }

    private Gauge createGauge(final GaugeKey gaugeKey) {
        return Gauge.build()
                .name(createProductNamespacedMetricName(GaugeNames.get(gaugeKey)))
                .help(GaugeDescriptions.get(gaugeKey))
                .labelNames(getLabelNames())
                .register();
    }

    private String createProductNamespacedMetricName(final String metricName) {
        final var productNameInMetricName = productName.replace("-", "_");
        return productNameInMetricName + '_' + metricName;
    }

    private static String[] getLabelNames() {
        return Arrays.stream(LabelKey.values()).map(LabelNames::get).toArray(String[]::new);
    }

    private String[] getLabelValues(final String kafkaTopic) {
        return new String[]{useCaseName, podName, outputType, kafkaTopic};
    }
}

[shivanisky]

You might want to migrate to mockito, as I hit the same issue.

Have built on @tinder-dthomson 's great work with much help from @timtebeek and added automation for more statements and improved robustness, including Jmockit Expectations, JMockit Verifications (v 8.29.0) and Jmockit NonStrictExpectations (v 8.30.0) . It's now looking like it would cover the majority of cases and may be worth exploring for migration to mockito

https://docs.openrewrite.org/recipes/java/testing/jmockit/jmockittomockito