Tune start script for OpenJDK 25 and use it in Docker image

app/src/main/scripts/unixStartScript.txt

@@ -43,9 +43,6 @@ cd "\$SAVED" >/dev/null
 APP_NAME="${applicationName}"
 APP_BASE_NAME=`basename "\$0"`
 
-# Add default JVM options here. You can also use JAVA_OPTS and ${optsEnvironmentVar} to pass JVM options to this script.
-DEFAULT_JVM_OPTS=${defaultJvmOpts}
-
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD="maximum"
 
@@ -105,6 +102,18 @@ Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
 
+JAVA_VERSION=`"\$JAVA_HOME/bin/java" -version 2>&1 | fgrep version | cut -d' ' -f3 | tr -d '"' | cut -d. -f1`
+
+# Add default JVM options here. You can also use JAVA_OPTS and ${optsEnvironmentVar} to pass JVM options to this script.
+if [ "\$JAVA_VERSION" -ge 25 ]; then
+    DEFAULT_JVM_OPTS=@DEFAULT_JVM_OPTS_25@
+elif [ "\$JAVA_VERSION" -ge 21 ]; then
+    DEFAULT_JVM_OPTS=${defaultJvmOpts}
+else
+    echo "Java version must be at least 21"
+    exit 1
+fi
+
 # Increase the maximum file descriptors if we can.
 if [ "\$cygwin" = "false" -a "\$darwin" = "false" -a "\$nonstop" = "false" ] ; then
     MAX_FD_LIMIT=`ulimit -H -n`

build.gradle

@@ -718,11 +718,14 @@ run {
   }
 }
 
-def tweakStartScript(createScriptTask) {
+def tweakStartScript(createScriptTask, defaultJvmOpts25) {
   def shortenWindowsClasspath = { line ->
     line.replaceAll(/^set CLASSPATH=.*$/, "set CLASSPATH=%APP_HOME%/lib/*")
   }
 
+  // this must be before the BESU_HOME replacement
+  createScriptTask.unixScript.text = createScriptTask.unixScript.text.replace('@DEFAULT_JVM_OPTS_25@', defaultJvmOpts25)
+
   createScriptTask.unixScript.text = createScriptTask.unixScript.text.replace('BESU_HOME', '\$APP_HOME')
   createScriptTask.windowsScript.text = createScriptTask.windowsScript.text.replace('BESU_HOME', '%~dp0..')
 
@@ -734,17 +737,28 @@ def tweakStartScript(createScriptTask) {
     .join('\r\n')
 }
 
+def defaultJvmOpts21 = application.applicationDefaultJvmArgs + [
+  "-XX:MaxHeapFreeRatio=30",
+  "-XX:MinHeapFreeRatio=10",
+  "-XX:MaxGCPauseMillis=100",
+  "-XX:StartFlightRecording,settings=default.jfc",
+  "-Xlog:jfr*=off"
+]
+
+def defaultJvmOpts25 = defaultJvmOpts21 + [
+  "-XX:+UseCompactObjectHeaders"
+]
+
+def serializeDefaultJvmOpts(opts) {
+  return "'" + opts.collect{ /"$it"/}.join(' ') + "'"
+}
+
 startScripts {
-  defaultJvmOpts = application.applicationDefaultJvmArgs + [
-    "-XX:G1ConcRefinementThreads=2",
-    "-XX:G1HeapWastePercent=15",
-    "-XX:MaxGCPauseMillis=100",
-    "-XX:StartFlightRecording,settings=default.jfc",
-    "-Xlog:jfr*=off"
-  ]
+  defaultJvmOpts = defaultJvmOpts21
   unixStartScriptGenerator.template = resources.text.fromFile("${projectDir}/app/src/main/scripts/unixStartScript.txt")
   windowsStartScriptGenerator.template = resources.text.fromFile("${projectDir}/app/src/main/scripts/windowsStartScript.txt")
-  doLast { tweakStartScript(startScripts) }
+
+  doLast { tweakStartScript(startScripts, serializeDefaultJvmOpts(defaultJvmOpts25)) }
 }
 
 task untunedStartScripts(type: CreateStartScripts) {
@@ -755,7 +769,7 @@ task untunedStartScripts(type: CreateStartScripts) {
   defaultJvmOpts = application.applicationDefaultJvmArgs
   unixStartScriptGenerator.template = resources.text.fromFile("${projectDir}/app/src/main/scripts/unixStartScript.txt")
   windowsStartScriptGenerator.template = resources.text.fromFile("${projectDir}/app/src/main/scripts/windowsStartScript.txt")
-  doLast { tweakStartScript(untunedStartScripts) }
+  doLast { tweakStartScript(untunedStartScripts, serializeDefaultJvmOpts(application.applicationDefaultJvmArgs)) }
 }
 
 task evmToolStartScripts(type: CreateStartScripts) {
@@ -768,7 +782,7 @@ task evmToolStartScripts(type: CreateStartScripts) {
   ]
   unixStartScriptGenerator.template = resources.text.fromFile("${projectDir}/app/src/main/scripts/unixStartScript.txt")
   windowsStartScriptGenerator.template = resources.text.fromFile("${projectDir}/app/src/main/scripts/windowsStartScript.txt")
-  doLast { tweakStartScript(evmToolStartScripts) }
+  doLast { tweakStartScript(evmToolStartScripts, serializeDefaultJvmOpts(defaultJvmOpts)) }
 }
 
 task autocomplete(type: JavaExec) {

docker/Dockerfile

@@ -1,7 +1,7 @@
 # syntax=docker/dockerfile:1
 
 # Stage: Use Eclipse Temurin JRE
-FROM eclipse-temurin:21-jre AS java-base
+FROM eclipse-temurin:25-jre AS java-base
 
 # Stage: Final Besu image
 FROM ubuntu:24.04