/**
  * Returns a fixed-size list backed by the specified array. (Changes to
  * the returned list "write through" to the array.) This method acts
  * as bridge between array-based and collection-based APIs, in
  * combination with {@link Collection#toArray}. The returned list is
  * serializable and implements {@link RandomAccess}.
  *
  * <p>This method also provides a convenient way to create a fixed-size
  * list initialized to contain several elements:
  * <pre>
  *  List<String> stooges = Arrays.asList("Larry", "Moe", "Curly");
  * </pre>
  *
  * @param a the array by which the list will be backed
  * @return a list view of the specified array
  */
 @SafeVarargs
 public static <T> List<T> asList(T... a) {
  return new ArrayList<>(a);
 }
 

/**
 * @author wangmengjun
 *
 */
public class ArrayExample {
 
 public static void main(String[] args) {
  
  /**使用变长参数*/
  List<String> array1 = Arrays.asList("Welcome", "to","Java", "world");
  System.out.println(array1);
  
  /**使用数组*/
  List<String> array2 = Arrays.asList(new String[] {"Welcome", "to","Java", "world"});
  System.out.println(array2);
 }

}

 /**使用变长参数*/
  List<String> array1 = Arrays.asList("Welcome", "to","Java", "world");
  array1.add("Cool~~~");

Exception in thread "main" java.lang.UnsupportedOperationException
 at java.util.AbstractList.add(Unknown Source)
 at java.util.AbstractList.add(Unknown Source)
 at test.ArrayExample.main(ArrayExample.java:36)

 /**
   * @serial include
   */
  private static class ArrayList<E> extends AbstractList<E>
    implements RandomAccess, java.io.Serializable
  {
    private static final long serialVersionUID = -2764017481108945198L;
    private final E[] a;

    ArrayList(E[] array) {
      if (array==null)
        throw new NullPointerException();
      a = array;
    }

    public int size() {
      return a.length;
    }

    public Object[] toArray() {
      return a.clone();
    }

    public <T> T[] toArray(T[] a) {
      int size = size();
      if (a.length < size)
        return Arrays.copyOf(this.a, size,
                   (Class<? extends T[]>) a.getClass());
      System.arraycopy(this.a, 0, a, 0, size);
      if (a.length > size)
        a[size] = null;
      return a;
    }

    public E get(int index) {
      return a[index];
    }

    public E set(int index, E element) {
      E oldValue = a[index];
      a[index] = element;
      return oldValue;
    }

    public int indexOf(Object o) {
      if (o==null) {
        for (int i=0; i<a.length; i++)
          if (a[i]==null)
            return i;
      } else {
        for (int i=0; i<a.length; i++)
          if (o.equals(a[i]))
            return i;
      }
      return -1;
    }

    public boolean contains(Object o) {
      return indexOf(o) != -1;
    }
  }

public abstract class AbstractList<E> extends AbstractCollection<E> implements List<E> {
  /**
   * Sole constructor. (For invocation by subclass constructors, typically
   * implicit.)
   */
  protected AbstractList() {
  }

  public E set(int index, E element) {
    throw new UnsupportedOperationException();
  }

  /**
   * {@inheritDoc}
   *
   * <p>This implementation always throws an
   * {@code UnsupportedOperationException}.
   *
   * @throws UnsupportedOperationException {@inheritDoc}
   * @throws ClassCastException      {@inheritDoc}
   * @throws NullPointerException     {@inheritDoc}
   * @throws IllegalArgumentException   {@inheritDoc}
   * @throws IndexOutOfBoundsException   {@inheritDoc}
   */
  public void add(int index, E element) {
    throw new UnsupportedOperationException();
  }

  /**
   * {@inheritDoc}
   *
   * <p>This implementation always throws an
   * {@code UnsupportedOperationException}.
   *
   * @throws UnsupportedOperationException {@inheritDoc}
   * @throws IndexOutOfBoundsException   {@inheritDoc}
   */
  public E remove(int index) {
    throw new UnsupportedOperationException();
  }
}

/**
 * @author wangmengjun
 *
 */
public class ArrayExample {

  public static void main(String[] args) {

    /**使用变长参数*/
    List<String> array1 = Arrays.asList("Welcome", "to", "Java", "world");
    array1.addAll(Arrays.asList("AAA", "BBB"));
  }

}

Exception in thread "main" java.lang.UnsupportedOperationException
 at java.util.AbstractList.add(Unknown Source)
 at java.util.AbstractList.add(Unknown Source)
 at java.util.AbstractCollection.addAll(Unknown Source)
 at test.ArrayExample.main(ArrayExample.java:36)
 

/**
 * @author wangmengjun
 *
 */
public class ArrayExample {

  public static void main(String[] args) {

    /**使用变长参数*/
    List<String> array1 = Arrays.asList("Welcome", "to", "Java", "world");
    System.out.println(array1);
    
    //将Java替换成hello
    array1.set(2, "hello");
    System.out.println(array1);
  }

}

/**
 * @author wangmengjun
 *
 */
public class ArrayExample {

  public static void main(String[] args) {

    /**使用变长参数*/
    List<String> array1 = new ArrayList<>(Arrays.asList("Welcome", "to", "Java", "world"));
    System.out.println(array1);

    array1.add("Cool~~~");
    System.out.println(array1);

  }

}