<bean name="moduleExecutorService" class="java.util.concurrent.ThreadPoolExecutor">
    <constructor-arg value="1" />   <!-- Minimun # of threads in pool -->
    <constructor-arg value="20" />  <!-- Maximum # of threads in pool (pool is a caching pool that will only keep open those necessary) -->
    <constructor-arg value="60" />  <!-- Shutdown unused threads after this TimeUnit -->
    <constructor-arg>
        <bean class="java.util.concurrent.TimeUnit" factory-method="valueOf">
            <constructor-arg value="SECONDS" />
        </bean>
    </constructor-arg>
    <constructor-arg type="java.util.concurrent.LinkedBlockingQueue"><bean class="java.util.concurrent.LinkedBlockingQueue" /></constructor-arg>
</bean>

446  [main] DEBUG org.springframework.beans.TypeConverterDelegate  - Cannot create copy of Collection type [java.util.concurrent.LinkedBlockingQueue] - injecting original Collection as-is
java.lang.InstantiationException: java.util.concurrent.BlockingQueue

public class ThreadPoolExecutorFactory implements FactoryBean
{
    private final ReentrantLock lock = new ReentrantLock();
    private ThreadPoolExecutor executor;
    private int corePoolSize;
    private int maximumPoolSize;
    private long keepAliveTime;
    private TimeUnit unit;

    public Object getObject()
    {
        lock.lock();
        if (executor == null)
            executor = new ThreadPoolExecutor(corePoolSize, maximumPoolSize,
                    keepAliveTime, unit, new LinkedBlockingQueue<Runnable>());
        lock.unlock();
        return executor;
    }

    public Class getObjectType()
    {
        return ThreadPoolExecutor.class;
    }

    public boolean isSingleton()
    {
        return true;
    }
}

<bean name="moduleExecutorService" class="ThreadPoolExecutorFactory">
    <constructor-arg value="1" />
    <constructor-arg value="20" />
    <constructor-arg value="60" />
    <constructor-arg>
        <bean class="java.util.concurrent.TimeUnit" factory-method="valueOf">
            <constructor-arg value="SECONDS" />
        </bean>
    </constructor-arg>
</bean>