Double-Checked Locking

[QiAnXinCodeSafe]

Alink/core/src/main/java/com/alibaba/alink/operator/common/nlp/jiebasegment/WordDictionary.java

Lines 48 to 52 in 963f0b8

	if (singleton == null) {
	synchronized (WordDictionary.class) {
	if (singleton == null) {
	singleton = new WordDictionary();
	return singleton;

Double-Checked Locking is widely cited and used as an efficient method for implementing lazy initialization in a multithreaded environment.
Unfortunately, it will not work reliably in a platform independent way when implemented in Java, without additional synchronization.
declares the singleton field volatile offers a much more elegant solution