Throw Exceptions in Consumer in Java 8

Throwing.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package hivemall.utils.lambda;

import java.util.function.Consumer;

import javax.annotation.Nonnull;

public final class Throwing {

    private Throwing() {}

    @Nonnull
    public static <T> Consumer<T> rethrow(@Nonnull final ThrowingConsumer<T> consumer) {
        return consumer;
    }

    /**
     * The compiler sees the signature with the throws T inferred to a RuntimeException type, so it
     * allows the unchecked exception to propagate.
     * 
     * http://www.baeldung.com/java-sneaky-throws
     */
    @SuppressWarnings("unchecked")
    @Nonnull
    public static <E extends Throwable> void sneakyThrow(@Nonnull Throwable ex) throws E {
        throw (E) ex;
    }

}

ThrowingConsumer.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package hivemall.utils.lambda;

import java.util.function.Consumer;

@FunctionalInterface
public interface ThrowingConsumer<T> extends Consumer<T> {

    @Override
    default void accept(final T e) {
        try {
            accept0(e);
        } catch (Throwable ex) {
            Throwing.sneakyThrow(ex);
        }
    }

    void accept0(T e) throws Throwable;

}

ThrowingTest.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package hivemall.utils.lambda;

import static hivemall.utils.lambda.Throwing.rethrow;

import java.io.IOException;
import java.util.Arrays;

import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.ExpectedException;

public class ThrowingTest {

    @Rule
    public ExpectedException thrown = ExpectedException.none();

    @Test
    public void testRethrow() {
        thrown.expect(IOException.class);
        thrown.expectMessage("i=3");

        Arrays.asList(1, 2, 3).forEach(rethrow(e -> {
            int i = e.intValue();
            if (i == 3) {
                throw new IOException("i=" + i);
            }
        }));
    }

    @Test(expected = IOException.class)
    public void testSneakyThrow() {
        Throwing.sneakyThrow(new IOException());
    }

    @Test
    public void testThrowingConsumer() {
        thrown.expect(IOException.class);
        thrown.expectMessage("i=3");

        Arrays.asList(1, 2, 3).forEach((ThrowingConsumer<Integer>) e -> {
            int i = e.intValue();
            if (i == 3) {
                throw new IOException("i=" + i);
            }
        });
    }

}

Nice :)
Shame you can't just use <E extends Throwable> void acceptThrows(T elem) throws E; in ThrowableConsumer and bypass Throwing.sneakyThrow