The following issues were found

src/main/java/io/reactivex/rxjava3/internal/operators/observable/ObservableMaterialize.java
3 issues
Found non-transient, non-static member. Please mark as transient or provide accessors.
Error

Line: 32 

                  }

    static final class MaterializeObserver<T> implements Observer<T>, Disposable {
        final Observer<? super Notification<T>> downstream;

        Disposable upstream;

        MaterializeObserver(Observer<? super Notification<T>> downstream) {
            this.downstream = downstream;

Reported by PMD.

Found non-transient, non-static member. Please mark as transient or provide accessors.
Error

Line: 34 

                  static final class MaterializeObserver<T> implements Observer<T>, Disposable {
        final Observer<? super Notification<T>> downstream;

        Disposable upstream;

        MaterializeObserver(Observer<? super Notification<T>> downstream) {
            this.downstream = downstream;
        }

Reported by PMD.

Avoid unused imports such as 'io.reactivex.rxjava3.core'
Design

Line: 16 

              
package io.reactivex.rxjava3.internal.operators.observable;

import io.reactivex.rxjava3.core.*;
import io.reactivex.rxjava3.disposables.Disposable;
import io.reactivex.rxjava3.internal.disposables.DisposableHelper;

public final class ObservableMaterialize<T> extends AbstractObservableWithUpstream<T, Notification<T>> {

Reported by PMD.

src/test/java/io/reactivex/rxjava3/internal/jdk8/FlatMapStream1HTckTest.java
3 issues
Potential violation of Law of Demeter (object not created locally)
Design

Line: 37 

                  @Override
    public Publisher<Integer> createFailedPublisher() {
        Stream<Integer> stream = Stream.of(1);
        stream.forEach(v -> { });
        return Flowable.just(1).hide().flatMapStream(v -> stream);
    }
}

Reported by PMD.

Potential violation of Law of Demeter (method chain calls)
Design

Line: 38 

                  public Publisher<Integer> createFailedPublisher() {
        Stream<Integer> stream = Stream.of(1);
        stream.forEach(v -> { });
        return Flowable.just(1).hide().flatMapStream(v -> stream);
    }
}

Reported by PMD.

Potential violation of Law of Demeter (method chain calls)
Design

Line: 38 

                  public Publisher<Integer> createFailedPublisher() {
        Stream<Integer> stream = Stream.of(1);
        stream.forEach(v -> { });
        return Flowable.just(1).hide().flatMapStream(v -> stream);
    }
}

Reported by PMD.

src/test/java/io/reactivex/rxjava3/internal/jdk8/FlatMapStream2HTckTest.java
3 issues
Potential violation of Law of Demeter (object not created locally)
Design

Line: 44 

                  @Override
    public Publisher<Integer> createFailedPublisher() {
        Stream<Integer> stream = Stream.of(1);
        stream.forEach(v -> { });
        return Flowable.just(1).hide().flatMapStream(v -> stream);
    }
}

Reported by PMD.

Potential violation of Law of Demeter (method chain calls)
Design

Line: 45 

                  public Publisher<Integer> createFailedPublisher() {
        Stream<Integer> stream = Stream.of(1);
        stream.forEach(v -> { });
        return Flowable.just(1).hide().flatMapStream(v -> stream);
    }
}

Reported by PMD.

Potential violation of Law of Demeter (method chain calls)
Design

Line: 45 

                  public Publisher<Integer> createFailedPublisher() {
        Stream<Integer> stream = Stream.of(1);
        stream.forEach(v -> { });
        return Flowable.just(1).hide().flatMapStream(v -> stream);
    }
}

Reported by PMD.

src/test/java/io/reactivex/rxjava3/internal/observers/CallbackCompletableObserverTest.java
3 issues
JUnit assertions should include a message
Design

Line: 29 

                  public void emptyActionShouldReportNoCustomOnError() {
        CallbackCompletableObserver o = new CallbackCompletableObserver(Functions.EMPTY_ACTION);

        assertFalse(o.hasCustomOnError());
    }

    @Test
    public void customOnErrorShouldReportCustomOnError() {
        CallbackCompletableObserver o = new CallbackCompletableObserver(Functions.<Throwable>emptyConsumer(),

Reported by PMD.

JUnit assertions should include a message
Design

Line: 37 

                      CallbackCompletableObserver o = new CallbackCompletableObserver(Functions.<Throwable>emptyConsumer(),
                Functions.EMPTY_ACTION);

        assertTrue(o.hasCustomOnError());
    }

}

Reported by PMD.

Avoid unused imports such as 'org.junit.Assert'
Design

Line: 16 

              
package io.reactivex.rxjava3.internal.observers;

import static org.junit.Assert.*;

import org.junit.Test;

import io.reactivex.rxjava3.core.RxJavaTest;
import io.reactivex.rxjava3.internal.functions.Functions;

Reported by PMD.

src/test/java/io/reactivex/rxjava3/internal/observers/ConsumerSingleObserverTest.java
3 issues
JUnit assertions should include a message
Design

Line: 30 

                      ConsumerSingleObserver<Integer> o = new ConsumerSingleObserver<>(Functions.<Integer>emptyConsumer(),
                Functions.ON_ERROR_MISSING);

        assertFalse(o.hasCustomOnError());
    }

    @Test
    public void customOnErrorShouldReportCustomOnError() {
        ConsumerSingleObserver<Integer> o = new ConsumerSingleObserver<>(Functions.<Integer>emptyConsumer(),

Reported by PMD.

JUnit assertions should include a message
Design

Line: 38 

                      ConsumerSingleObserver<Integer> o = new ConsumerSingleObserver<>(Functions.<Integer>emptyConsumer(),
                Functions.<Throwable>emptyConsumer());

        assertTrue(o.hasCustomOnError());
    }

}

Reported by PMD.

Avoid unused imports such as 'org.junit.Assert'
Design

Line: 16 

              
package io.reactivex.rxjava3.internal.observers;

import static org.junit.Assert.*;

import org.junit.Test;

import io.reactivex.rxjava3.core.RxJavaTest;
import io.reactivex.rxjava3.internal.functions.Functions;

Reported by PMD.

src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableConcatArrayDelayErrorTest.java
3 issues
Potential violation of Law of Demeter (method chain calls)
Design

Line: 38 

                      .test()
        .assertFailure(TestException.class);

        verify(action1).run();

        verify(action2).run();
    }

}

Reported by PMD.

Potential violation of Law of Demeter (method chain calls)
Design

Line: 40 

              
        verify(action1).run();

        verify(action2).run();
    }

}

Reported by PMD.

Avoid unused imports such as 'org.mockito.Mockito'
Design

Line: 16 

              
package io.reactivex.rxjava3.internal.operators.completable;

import static org.mockito.Mockito.*;
import org.junit.Test;

import io.reactivex.rxjava3.core.Completable;
import io.reactivex.rxjava3.exceptions.TestException;
import io.reactivex.rxjava3.functions.Action;

Reported by PMD.

src/test/java/io/reactivex/rxjava3/completable/CapturingUncaughtExceptionHandler.java
3 issues
Found non-transient, non-static member. Please mark as transient or provide accessors.
Error

Line: 19 

              import java.util.concurrent.CountDownLatch;

public final class CapturingUncaughtExceptionHandler implements Thread.UncaughtExceptionHandler {
    public int count;
    public Throwable caught;
    public CountDownLatch completed = new CountDownLatch(1);

    @Override
    public void uncaughtException(Thread t, Throwable e) {

Reported by PMD.

Found non-transient, non-static member. Please mark as transient or provide accessors.
Error

Line: 20 

              
public final class CapturingUncaughtExceptionHandler implements Thread.UncaughtExceptionHandler {
    public int count;
    public Throwable caught;
    public CountDownLatch completed = new CountDownLatch(1);

    @Override
    public void uncaughtException(Thread t, Throwable e) {
        count++;

Reported by PMD.

Found non-transient, non-static member. Please mark as transient or provide accessors.
Error

Line: 21 

              public final class CapturingUncaughtExceptionHandler implements Thread.UncaughtExceptionHandler {
    public int count;
    public Throwable caught;
    public CountDownLatch completed = new CountDownLatch(1);

    @Override
    public void uncaughtException(Thread t, Throwable e) {
        count++;
        caught = e;

Reported by PMD.

src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleContainstTest.java
3 issues
JUnit tests should include assert() or fail()
Design

Line: 25 

              public class SingleContainstTest extends RxJavaTest {

    @Test
    public void comparerThrows() {
        Single.just(1)
        .contains(2, new BiPredicate<Object, Object>() {
            @Override
            public boolean test(Object a, Object b) throws Exception {
                throw new TestException();

Reported by PMD.

JUnit tests should include assert() or fail()
Design

Line: 38 

                  }

    @Test
    public void error() {
        Single.error(new TestException())
        .contains(2)
        .test()
        .assertFailure(TestException.class);
    }

Reported by PMD.

Avoid unused imports such as 'io.reactivex.rxjava3.core'
Design

Line: 18 

              
import org.junit.Test;

import io.reactivex.rxjava3.core.*;
import io.reactivex.rxjava3.exceptions.TestException;
import io.reactivex.rxjava3.functions.BiPredicate;

public class SingleContainstTest extends RxJavaTest {

Reported by PMD.

src/test/java/io/reactivex/rxjava3/internal/operators/flowable/AbstractFlowableWithUpstreamTest.java
3 issues
Potential violation of Law of Demeter (object not created locally)
Design

Line: 31 

                  public void source() {
        Flowable<Integer> f = Flowable.just(1);

        assertSame(f, ((HasUpstreamPublisher<Integer>)f.map(Functions.<Integer>identity())).source());
    }
}

Reported by PMD.

JUnit assertions should include a message
Design

Line: 31 

                  public void source() {
        Flowable<Integer> f = Flowable.just(1);

        assertSame(f, ((HasUpstreamPublisher<Integer>)f.map(Functions.<Integer>identity())).source());
    }
}

Reported by PMD.

Avoid unused imports such as 'io.reactivex.rxjava3.core'
Design

Line: 20 

              
import org.junit.Test;

import io.reactivex.rxjava3.core.*;
import io.reactivex.rxjava3.internal.functions.Functions;
import io.reactivex.rxjava3.internal.fuseable.HasUpstreamPublisher;

public class AbstractFlowableWithUpstreamTest extends RxJavaTest {

Reported by PMD.

src/main/java/io/reactivex/rxjava3/subscribers/DisposableSubscriber.java
3 issues
Found non-transient, non-static member. Please mark as transient or provide accessors.
Error

Line: 77 

               * @param <T> the received value type.
 */
public abstract class DisposableSubscriber<T> implements FlowableSubscriber<T>, Disposable {
    final AtomicReference<Subscription> upstream = new AtomicReference<>();

    @Override
    public final void onSubscribe(Subscription s) {
        if (EndConsumerHelper.setOnce(this.upstream, s, getClass())) {
            onStart();

Reported by PMD.

Potential violation of Law of Demeter (method chain calls)
Design

Line: 90 

                   * Called once the single upstream {@link Subscription} is set via {@link #onSubscribe(Subscription)}.
     */
    protected void onStart() {
        upstream.get().request(Long.MAX_VALUE);
    }

    /**
     * Requests the specified amount from the upstream if its {@link Subscription} is set via
     * onSubscribe already.

Reported by PMD.

Potential violation of Law of Demeter (method chain calls)
Design

Line: 102 

                   * @param n the request amount, positive
     */
    protected final void request(long n) {
        upstream.get().request(n);
    }

    /**
     * Cancels the Subscription set via {@link #onSubscribe(Subscription)} or makes sure a
     * {@link Subscription} set asynchronously (later) is cancelled immediately.

Reported by PMD.