Double-Checked Locking

[QiAnXinCodeSafe]

Priam/priam/src/main/java/com/netflix/priam/aws/S3CrossAccountFileSystem.java

Lines 65 to 68 in a78b203

	if (this.s3Client == null) {
	synchronized (this) {
	if (this.s3Client == null) {

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.

[mattl-netflix]

Thanks for the insights! I have a couple follow-up questions though:

Will it work as expected on an x86 architecture?
Also, would you give an example of the additional synchronization needed?