Chapter 1. Overview of alt-java

The family of Spectre/Meltdown vulnerabilities includes Speculative Store Bypass (SSB), which may affect the Java VM (CVE-2018-3639).

Red Hat packages contain a mitigation for this vulnerability in the form of a patch for the Java binary. However, this patch reduces performance by up to 10% in some cases. This is described in RH1566890.

Since the patch reduces performance, it has been removed from the “java” launcher. A new binary “alt-java” is now available. From the January 2021 CPU release (1.8.0 282.b08, 11.0.10.9) onwards the alt-java binary is included in OpenJDK 1.8.0 and 11 GA rpms.