diff --git a/scripts/prerequisites.sh b/scripts/prerequisites.sh
index 97ac7e7e..0dd1d44a 100755
--- a/scripts/prerequisites.sh
+++ b/scripts/prerequisites.sh
@@ -158,8 +158,6 @@ extras="\
 "
 
 # add ppa for openjdk
-java_version=`java -version 2>&1 | head -n 1 | cut -d\" -f 2 | cut -d\. -f 1`
-
 add-apt-repository ppa:openjdk-r/ppa --yes
 apt-get update
 
@@ -168,6 +166,7 @@ apt-get install --yes \
     ${extras} \
     ${archivers} \
 
+java_version=`java -version 2>&1 | head -n 1 | cut -d\" -f 2 | cut -d\. -f 1`
 if [ -z $java_version ] || [ $java_version -lt 10 ]; then
     update-alternatives --set java /usr/lib/jvm/java-11-openjdk-amd64/bin/java
 fi