Method containsKey

lib/java/util/Hashtable.java:372–374

Returns true if this Hashtable contains the specified object as a key of one of the key/value pairs. @param key the object to look for as a key in this Hashtable. @return true if object is a key in this Hashtable, false otherwise. @see #con

(Object key)

     * @see java.lang.Object#equals
     */
    public synchronized boolean containsKey(Object key) {
        return getEntry(key) != null;
    }

    /**
     * Searches this {@code Hashtable} for the specified value.