请问

[jeyhan]

No description provided.

[Jacksgong]

是的。这里是对相同内容的String进行同步。

/**
 * Returns an interned string equal to this string. The VM maintains an internal set of
 * unique strings. All string literals found in loaded classes'
 * constant pools are automatically interned. Manually-interned strings are only weakly
 * referenced, so calling {@code intern} won't lead to unwanted retention.
 *
 * <p>Interning is typically used because it guarantees that for interned strings
 * {@code a} and {@code b}, {@code a.equals(b)} can be simplified to
 * {@code a == b}. (This is not true of non-interned strings.)
 *
 * <p>Many applications find it simpler and more convenient to use an explicit
 * {@link java.util.HashMap} to implement their own pools.
 */
public native String intern();

[Jacksgong]

通常如果是成员变量作为锁的话，确实跑一些inspection的时候，会有这样的提示，目的就是防止由于变量发生改变导致同一个变量，但是由于指向不同的对象，导致锁作用在不同的对象上。

这里使用 eventId.intern() 就是保证了无论是哪个eventId，只要是同样的内容，就是对同一个对象进行加锁。这里并没有对什么作为拓展，就是完成: 对相同eventId的事件进行加锁。