Вывести объект на консоль ввиде строк

package test;

import ex21.Address21;
import ex21.Customer21;
import org.junit.Assert;
import org.junit.Test;

import javax.persistence.Query;
import java.util.Arrays;
import java.util.List;

public class Queries21AIT extends AbstractPersistentTest {

    private static final int ALL = 6;

    @Test
    public void shouldFindAllWithANamedQueries() throws Exception {

        Customer21 customer01 = new Customer21("Antony", "Balla", "[email protected]", 14);
        Address21 address01 = new Address21("Procession St", "Paris", "75015", "FR");
        customer01.setAddress(address01);

        Customer21 customer02 = new Customer21("Vincent", "Johnson", "[email protected]", 45);
        Address21 address02 = new Address21("Ritherdon Rd", "London", "8QE", "UK");
        customer02.setAddress(address02);

        Customer21 customer03 = new Customer21("Sebastian", "Twenty", "[email protected]", 58);
        Address21 address03 = new Address21("Inacio Alfama", "Lisbon", "A54", "PT");
        customer03.setAddress(address03);

        Customer21 customer04 = new Customer21("Frederic", "Riou", "[email protected]", 41);
        Address21 address04 = new Address21("Jardins", "Sao Paulo", "345678", "BR");
        customer04.setAddress(address04);

        Customer21 customer05 = new Customer21("Vincent", "Dubosc", "[email protected]", 14);
        Address21 address05 = new Address21("Coffey", "Perth", "654F543", "AU");
        customer05.setAddress(address05);

        Customer21 customer06 = new Customer21("David", "Chene", "[email protected]", 89);
        Address21 address06 = new Address21("Harbour Bridge", "Sydney", "JHG3", "AU");
        customer06.setAddress(address06);


        // Persist the object
        tx.begin();
        em.persist(customer01);
        em.persist(customer02);
        em.persist(customer03);
        em.persist(customer04);
        em.persist(customer05);
        em.persist(customer06);
        tx.commit();

        Query query = em.createQuery("select  c from Customer21 c");
        List<Customer21> customer21s1 = query.getResultList();
        Assert.assertEquals(ALL, customer21s1.size());

        query = em.createQuery("select c.firstName from Customer21 c");
        List<String> customer21s2 = query.getResultList();
        Assert.assertEquals(ALL, customer21s2.size());

        query = em.createQuery("select LOWER(c.firstName) from Customer21 c");
        List<String> customer21s3 = query.getResultList();
        Assert.assertEquals(ALL, customer21s3.size());

        query = em.createQuery("select c.firstName, c.lastName from Customer21 c");
        List<Customer21> customer21s4 = query.getResultList();
        Assert.assertEquals(ALL, customer21s4.size());
        for(Customer21 customer21: customer21s4){
            System.out.println(customer21.getFirstName() + " " + customer21.getLastName());
        }
    }
}

java.lang.ClassCastException: [Ljava.lang.Object; cannot be cast to ex21.Customer21

    at test.Queries21AIT.shouldFindAllWithANamedQueries(Queries21AIT.java:69)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:59)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:56)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
    at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
    at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)
    at org.junit.runners.BlockJUnit4ClassRunner$1.evaluate(BlockJUnit4ClassRunner.java:100)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:366)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:103)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:63)
    at org.junit.runners.ParentRunner$4.run(ParentRunner.java:331)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:79)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:329)
    at org.junit.runners.ParentRunner.access$100(ParentRunner.java:66)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:293)
    at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:413)
    at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
    at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
    at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)
    at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:230)
    at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:58)

Подскажите как можно вывести объект виде строк, пака только получилось вывести как объект