"should return different hash codes for non equal objects" with 0.7.5

[ade90036]

I have a POJO and using intelliJ i've created toString, equals, hashCode methods.

package com.arizzini.api.model;

import com.arizzini.api.runner.Response;
import com.arizzini.api.core.model.Environment;

import java.io.Serializable;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * Created by arizzini on 11/2/16.
 */
public class ServiceObject implements Serializable {
    public final String version;
    public final String title;
    public final String artifactId;
    public final String host;
    public final String context;
    public final Environment environment;
    public final List<OperationObject> operationObjects;
    public final boolean hasOrdering;

    public Integer elapseTimeSeconds;
    public Date lastRun;
    public Map<String,Response> responseMap;


    public ServiceObject(String artifactId, String title, String version, String host, String context, Environment environment, List<OperationObject> operationObjects, boolean hasOrdering) {
        this.version = version;
        this.title = title;
        this.artifactId = artifactId;
        this.host = host;
        this.context = context;
        this.environment = environment;
        this.operationObjects = operationObjects;
        this.responseMap = new HashMap<>();
        this.hasOrdering = hasOrdering;
    }

    public void clearResponseMap() {
        responseMap.clear();
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

        ServiceObject that = (ServiceObject) o;

        if (hasOrdering != that.hasOrdering) return false;
        if (version != null ? !version.equals(that.version) : that.version != null) return false;
        if (title != null ? !title.equals(that.title) : that.title != null) return false;
        if (artifactId != null ? !artifactId.equals(that.artifactId) : that.artifactId != null) return false;
        if (host != null ? !host.equals(that.host) : that.host != null) return false;
        if (context != null ? !context.equals(that.context) : that.context != null) return false;
        if (environment != that.environment) return false;
        return true;
    }

    @Override
    public int hashCode() {
        int result = version != null ? version.hashCode() : 0;
        result = 31 * result + (title != null ? title.hashCode() : 0);
        result = 31 * result + (artifactId != null ? artifactId.hashCode() : 0);
        result = 31 * result + (host != null ? host.hashCode() : 0);
        result = 31 * result + (context != null ? context.hashCode() : 0);
        result = 31 * result + (environment != null ? environment.hashCode() : 0);
        result = 31 * result + (operationObjects != null ? operationObjects.hashCode() : 0);
        result = 31 * result + (hasOrdering ? 1 : 0);
        return result;
    }

    @Override
    public String toString() {
        final StringBuffer sb = new StringBuffer("ServiceObject{");
        sb.append("version='").append(version).append('\'');
        sb.append(", title='").append(title).append('\'');
        sb.append(", artifactId='").append(artifactId).append('\'');
        sb.append(", host='").append(host).append('\'');
        sb.append(", context='").append(context).append('\'');
        sb.append(", environment=").append(environment);
        sb.append(", operationObjects=").append(operationObjects);
        sb.append(", hasOrdering=").append(hasOrdering);
        sb.append('}');
        return sb.toString();
    }
}

When i run the test i'm getting the following:

Class com.arizzini.api.model.ServiceObject has bad 'hashCode' method implementation.
The hashCode method should return different hash codes for non equal objects.
Current implementation returns same hash codes.
Object:
ServiceObject{version='www.pojo.pl', title='www.pojo.pl', artifactId='www.pojo.pl', host='www.pojo.pl', context='www.pojo.pl', environment=PRODUCTION, operationObjects=[], hasOrdering=true}
and
ServiceObject{version='www.pojo.pl', title='www.pojo.pl', artifactId='www.pojo.pl', host='www.pojo.pl', context='www.pojo.pl', environment=PRODUCTION, operationObjects=[], hasOrdering=true}
should have different hash codes:
-923710817
and
-923710817

And the test looks like this:

@Test   
 public void  ServiceObjectPojoOperations()  throws Exception {
        // given
        final Class<?> classUnderTest = ServiceObject.class;

        // when


        // then
        assertPojoMethodsFor(classUnderTest)
                .testing(Method.CONSTRUCTOR)
                .testing(Method.EQUALS)
                .testing(Method.HASH_CODE)
                .testing(Method.TO_STRING)
                .areWellImplemented();
    }

Is there a way i can debug what is going on?
The error message is a bit confusing...
The test failure is clearly stated here: "The hashCode method should return different hash codes for non equal objects.", however, when the two objects are printed in the following statements they appear to be identical??

Should it be printing the actual objects which is trying to generate the hashCode instead?

Any ideas how i could fix this?

I'm not using Date, (in the hashCode).

BTW: i 0.7.5 is not in maven central so i had manually include the jar in my project lib folder.

Regards

[sta-szek]

Hi, thanks for reporting an issue ;)

First of all, pojo-tester is published only to bintray, so you can use it as dependency in your build - just define jcenter as repository as described in here http://stackoverflow.com/questions/31961025/using-jcenter-and-mavencentral-both-in-android-studio.

Second, you can debug by enabling DEBUG level on your logger when you perform tests. See more at http://www.pojo.pl/writing-tests/#debugging.

Third, at first glance I can spy with my little eye, that the assertion exception is good because:

• You tell to pojo-tester: "test this class changing all of its fields". So it changes all of them including: elapseTimeSeconds, lastRun, responseMap. And you didn't implement them in toString() method, so you can't see in log, that they are actually different - they can have different e.g. lastRun field.
  If you don't want to test those fields, just exclude them as described here http://www.pojo.pl/writing-tests/#choosing-fields

• Your equals and hashcode methods seem to be wrong implemented because you included operationObjects in equals implementation but forgot / didn't include it in hashcode implementation.

Let me know if this answer is satisfactory.

[sta-szek]

@ade90036 do you still have the problem?