diff --git a/java-21-openjdk.spec b/java-21-openjdk.spec
index bde37f5..07e54c9 100644
--- a/java-21-openjdk.spec
+++ b/java-21-openjdk.spec
@@ -1845,6 +1845,7 @@ if [ %{include_debug_build} -eq 0 -a  %{include_normal_build} -eq 0 -a  %{includ
   exit 14
 fi
 
+export XZ_OPT="-T0"
 %setup -q -c -n %{uniquesuffix ""} -T -a 0
 # https://bugzilla.redhat.com/show_bug.cgi?id=1189084
 prioritylength=`expr length %{priority}`
@@ -1922,6 +1923,8 @@ function customisejdk() {
     fi
 }
 
+export XZ_OPT="-T0"
+
 mkdir -p $(dirname %{installoutputdir})
 
 docdir=%{installoutputdir -- "-docs"}
@@ -2485,6 +2488,10 @@ cjc.mainProgram(args)
 %endif
 
 %changelog
+* Sun Apr 14 2024 Thomas Fitzsimmons <fitzsim@redhat.com> - 1:21.0.3.0.1-0.2.ea
+- Invoke xz in multi-threaded mode
+- Related: RHEL-30946
+
 * Sun Apr 14 2024 Andrew Hughes <gnu.andrew@redhat.com> - 1:21.0.3.0.1-0.2.ea
 - rebuilt
 - Related: RHEL-30946