/**
     * {@link Thread} for the timer.
     */
    protected Thread thread;

    /**
     * A list for managing {@link TimeoutTask}.
     */
    protected final SLinkedList<TimeoutTask> timeoutTaskList = new SLinkedList<>();

    private TimeoutManager() {
    }

    /**
     * Returns the instance for the singleton.
     *
     * @return the instance for the singleton
     */

import org.codelibs.core.io.SerializeUtil;
import org.junit.Test;

/**
 * @author higa
 */
public class SLinkedListTest {

    private final SLinkedList<String> list = new SLinkedList<String>();

    /**
     * @throws Exception
     */
    @Test
    public void testGetFirstEntry() throws Exception {
        assertThat(list.getFirstEntry(), is(nullValue()));