From a94db0317c2e0c7fca36697678e9d742f8d76fe9 Mon Sep 17 00:00:00 2001
From: sstone <fabrice@acinq.fr>
Date: Thu, 17 Oct 2024 19:32:56 +0200
Subject: [PATCH] Target Java 21

Eclair now targets Java 21 and will require a compatible Java Runtime Environment.
It will no longer work on JRE 11 and JRE 17.
---
 .github/workflows/latest-bitcoind.yml                       | 4 ++--
 README.md                                                   | 2 +-
 docs/release-notes/eclair-vnext.md                          | 4 ++++
 .../acinq/eclair/wire/protocol/LightningMessageTypes.scala  | 6 +++++-
 eclair-node/src/main/scala/fr/acinq/eclair/Plugin.scala     | 5 ++---
 pom.xml                                                     | 4 ++--
 6 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/.github/workflows/latest-bitcoind.yml b/.github/workflows/latest-bitcoind.yml
index 26ea8ad60c..3ad462e1f1 100644
--- a/.github/workflows/latest-bitcoind.yml
+++ b/.github/workflows/latest-bitcoind.yml
@@ -38,10 +38,10 @@ jobs:
         with:
           path: eclair
 
-      - name: Set up JDK 11
+      - name: Set up JDK 21
         uses: actions/setup-java@v3
         with:
-          java-version: 11
+          java-version: 21
           distribution: 'adopt'
 
       - name: Configure OS settings
diff --git a/README.md b/README.md
index b9d531fb60..d6dae00fad 100644
--- a/README.md
+++ b/README.md
@@ -94,7 +94,7 @@ rpcclienttimeout=30
 
 Eclair is developed in [Scala](https://www.scala-lang.org/), a powerful functional language that runs on the JVM, and is packaged as a ZIP archive.
 
-To run Eclair, you first need to install Java. Eclair targets Java 11 and will run on any compatible Java runtime (including 11, 17 and 21), we recommend that you use [OpenJDK 21](https://adoptium.net/temurin/releases/?package=jdk&version=21).
+To run Eclair, you first need to install Java. Eclair targets Java 21 and will run on any compatible Java runtime, we recommend that you use [OpenJDK 21](https://adoptium.net/temurin/releases/?package=jdk&version=21).
 
 Then download our latest [release](https://github.com/ACINQ/eclair/releases), unzip the archive and run the following command:
 
diff --git a/docs/release-notes/eclair-vnext.md b/docs/release-notes/eclair-vnext.md
index cc7ba22d9f..7a139285af 100644
--- a/docs/release-notes/eclair-vnext.md
+++ b/docs/release-notes/eclair-vnext.md
@@ -6,6 +6,10 @@
 
 <insert changes>
 
+### Eclair requires a  Java 21 runtime
+
+Eclair now targets Java 21 and requires a compatible Java Runtime Environment. It will no longer work on JRE 11 or JRE 17.
+
 ### API changes
 
 <insert changes>
diff --git a/eclair-core/src/main/scala/fr/acinq/eclair/wire/protocol/LightningMessageTypes.scala b/eclair-core/src/main/scala/fr/acinq/eclair/wire/protocol/LightningMessageTypes.scala
index 40cc0633c1..b73a67905e 100644
--- a/eclair-core/src/main/scala/fr/acinq/eclair/wire/protocol/LightningMessageTypes.scala
+++ b/eclair-core/src/main/scala/fr/acinq/eclair/wire/protocol/LightningMessageTypes.scala
@@ -491,7 +491,11 @@ object NodeAddress {
 }
 
 object IPAddress {
-  def apply(inetAddress: InetAddress, port: Int): IPAddress = inetAddress match {
+  def apply(inetAddress: InetAddress, port: Int): IPAddress = (inetAddress: @unchecked) match {
+    // we need the @unchecked annotation to suppress a "matching not exhaustive". Before JDK21, InetAddress was a regular so scalac would not check anything (it only checks sealed patterns)
+    // with JDK21 InetAddress is defined as `public sealed class InetAddress implements Serializable permits Inet4Address, Inet6Address` and scalac complains because in theory there could be
+    // an InetAddress() instance, though its not possible in practice because the constructor is package private :(
+    // remove @unchecked if we upgrade to a newer JDK that does not have this pb, or if scalac pattern matching becomes more clever
     case address: Inet4Address => IPv4(address, port)
     case address: Inet6Address => IPv6(address, port)
   }
diff --git a/eclair-node/src/main/scala/fr/acinq/eclair/Plugin.scala b/eclair-node/src/main/scala/fr/acinq/eclair/Plugin.scala
index d7e4100434..2cc9cffd20 100644
--- a/eclair-node/src/main/scala/fr/acinq/eclair/Plugin.scala
+++ b/eclair-node/src/main/scala/fr/acinq/eclair/Plugin.scala
@@ -17,8 +17,7 @@
 package fr.acinq.eclair
 
 import java.io.File
-import java.net.{JarURLConnection, URL, URLClassLoader}
-
+import java.net.{JarURLConnection, URI, URL, URLClassLoader}
 import akka.http.scaladsl.server.Route
 import fr.acinq.eclair.api.directives.EclairDirectives
 import grizzled.slf4j.Logging
@@ -59,7 +58,7 @@ object Plugin extends Logging {
   }
 
   def openJar(jar: File): Option[JarURLConnection] =
-    Try(new URL(s"jar:file:${jar.getCanonicalPath}!/").openConnection().asInstanceOf[JarURLConnection]) match {
+    Try(URI.create(s"jar:file:${jar.getCanonicalPath}!/").toURL.openConnection().asInstanceOf[JarURLConnection]) match {
       case Success(url) => Some(url)
       case Failure(t) => logger.error(s"unable to load plugin file:${jar.getAbsolutePath} ", t); None
     }
diff --git a/pom.xml b/pom.xml
index 15d4c2745c..7cac4c3725 100644
--- a/pom.xml
+++ b/pom.xml
@@ -65,8 +65,7 @@
     <properties>
         <project.build.outputTimestamp>2020-01-01T00:00:00Z</project.build.outputTimestamp>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-        <maven.compiler.source>11</maven.compiler.source>
-        <maven.compiler.target>11</maven.compiler.target>
+        <maven.compiler.release>21</maven.compiler.release>
         <scala.version>2.13.11</scala.version>
         <scala.version.short>2.13</scala.version.short>
         <akka.version>2.6.20</akka.version>
@@ -151,6 +150,7 @@
                         <arg>-Werror</arg>
                         <arg>-unchecked</arg>
                         <arg>-deprecation</arg>
+                        <arg>-release:21</arg>
                     </args>
                     <jvmArgs>
                         <jvmArg>-Xmx1024m</jvmArg>