DOCCORE-293 fixed error in debian installs. Updated java instructions to j21 (#3067)

Author: jennyowen

modules/ROOT/pages/installation/linux/debian.adoc

@@ -8,9 +8,7 @@ You can install Neo4j on Debian, and Debian-based distributions like Ubuntu, usi
 == Java prerequisites
 
 Neo4j {neo4j-version} requires the Java 17 runtime.
-Java 17 is not included in Ubuntu 16.04 LTS and will have to be set up manually before installing or upgrading to Neo4j {neo4j-version}, as described below.
-Debian 11 and Ubuntu 18.04 onwards already have the OpenJDK Java 17 package available through `apt`.
-From version 5.14 onwards, Neo4j also supports JDK 21.
+From version 5.14 onwards, Neo4j also supports Java 21.
 
 [[debian-prerequisites-notopenjdk]]
 === Oracle JDK, Zulu JDK, or Corretto JDK
@@ -25,25 +23,10 @@ Download and installation instructions can be found on the manufacturer's websit
 * https://aws.amazon.com/corretto/[Amazon Corretto JDK]
 
 
-[[ubuntu-java17]]
-=== OpenJDK 17 on Ubuntu 16.04
-
-Add the official OpenJDK package repository to `apt`:
-
-[source, shell]
-----
-sudo add-apt-repository -y ppa:openjdk-r/ppa
-sudo apt-get update
-----
-
-You are now ready to install Neo4j, which will install Java 17 automatically if it is not already installed.
-See xref:installation/linux/debian.adoc#multiple-java-versions[Dealing with multiple installed Java versions] to make sure you can start Neo4j after installation.
-
-
 [[multiple-java-versions]]
 === Dealing with multiple installed Java versions
 
-You must configure your default Java version to point to Java 17, or Neo4j {neo4j-version-exact} will be unable to start.
+You must configure your default Java version to point to Java 17 or 21, or Neo4j {neo4j-version-exact} will be unable to start.
 Do so with the `update-java-alternatives` command.
 
 . List all your installed versions of Java with `update-java-alternatives --list`.
@@ -52,27 +35,21 @@ Your results may vary, but this is an example of the output:
 +
 [queryresult]
 ----
+java-1.11.0-openjdk-amd64 1111 /usr/lib/jvm/java-1.11.0-openjdk-amd64
 java-1.17.0-openjdk-amd64 1711 /usr/lib/jvm/java-1.17.0-openjdk-amd64
-java-1.11.0-openjdk-amd64 1071 /usr/lib/jvm/java-1.11.0-openjdk-amd64
+java-1.21.0-openjdk-amd64 2111 /usr/lib/jvm/java-1.21.0-openjdk-amd64
 ----
 
-. Identify your Java 17 version:
-+
-[source, shell]
-----
-java -version
-----
-+
-In this case, it is `java-1.17.0-openjdk-amd64`.
+. Identify your Java 21 version, in this case, it is `java-1.21.0-openjdk-amd64`.
 
-. Set it as the default by replacing `<java17name>` with its name:
+. Set it as the default by replacing `<java21name>` with its name:
 +
 [source, shell]
 ----
-sudo update-java-alternatives --jre --set <java17name>
+sudo update-java-alternatives --jre --set <java21name>
 ----
 
-. Confirm which version of Java is the default using `java -version` again.
+. Confirm which version of Java is the default using `java -version`.
 
 [[debian-installation]]
 == Installation
@@ -108,7 +85,7 @@ sudo chmod a+r /etc/apt/keyrings/neotechnology.gpg
 +
 [source,bash]
 ----
-echo 'deb [signed-by=/etc/apt/keyrings/neotechnology.gpg] https://debian.neo4j.com stable 5.26' | sudo tee -a /etc/apt/sources.list.d/neo4j.list > /dev/null
+echo 'deb [signed-by=/etc/apt/keyrings/neotechnology.gpg] https://debian.neo4j.com stable 5' | sudo tee -a /etc/apt/sources.list.d/neo4j.list > /dev/null
 ----
 . Update package lists:
 +
@@ -190,38 +167,38 @@ echo "neo4j-enterprise neo4j/license note" | sudo debconf-set-selections
 [[debian-install-newer-java]]
 === Verify the Java version
 
-On newer Debian or Ubuntu operating systems, Java 19 is available by default, and `apt` may install OpenJDK 19, *even if you have Java 17 installed*.
+On newer Debian or Ubuntu operating systems, Java 25 is available by default, and `apt` may install OpenJDK 25, *even if you have Java 21 installed*.
 
 If this happens, Neo4j will return the following warning on start:
 [output]
 ----
 WARNING! You are using an unsupported Java runtime.
-* Please use Oracle(R) Java(TM) 17, OpenJDK(TM) 17 to run Neo4j.
+* Please use Oracle(R) Java(TM) 25, OpenJDK(TM) 25 to run Neo4j.
 * Please see https://neo4j.com/docs/ for Neo4j installation instructions.
 ----
 
-To fix this, you can install Java 17 manually and then either uninstall OpenJDK 19 or set Java 17 as the default.
+To fix this, you can install Java 21 manually and then either uninstall OpenJDK 25 or set Java 21 as the default.
 
-. Run the following command to install OpenJDK 17 manually:
+. Run the following command to install OpenJDK 21 manually:
 +
 [source, shell, subs="attributes"]
 ----
-sudo apt install openjdk-17-jre
+sudo apt install openjdk-21-jre
 ----
 +
-For other distributions of Java 17, see
+For other distributions of Java, see
 xref:installation/linux/debian.adoc#debian-prerequisites-notopenjdk[Java prerequisites].
 
 . Choose one of the following options to set it as the default:
 +
-* Uninstall OpenJDK 19:
+* Uninstall OpenJDK 25:
 +
 [source, shell, subs="attributes"]
 ----
-sudo apt remove openjdk-19-jre-headless
+sudo apt remove openjdk-25-jre-headless
 ----
 
-* If you want to keep OpenJDK 19 installed, set Java 17 as default by following the instructions in
+* If you want to keep OpenJDK 25 installed, set Java 21 as default by following the instructions in
 xref:installation/linux/debian.adoc#multiple-java-versions[Dealing with multiple installed Java versions].