gradle: Improve toolchains test (#395965)

pkgs/development/tools/build-managers/gradle/default.nix

@@ -1,5 +1,4 @@
 {
-  jdk11,
   jdk17,
   jdk21,
   jdk23,
@@ -286,27 +285,27 @@ rec {
             unwrapped = gradle;
             tests = {
               toolchains =
+                let
+                  javaVersion = lib.versions.major (lib.getVersion jdk23);
+                in
                 runCommand "detects-toolchains-from-nix-env"
                   {
                     # Use JDKs that are not the default for any of the gradle versions
                     nativeBuildInputs = [
                       (gradle.override {
                         javaToolchains = [
-                          jdk11
                           jdk23
                         ];
                       })
                     ];
-                    src = ./tests/java-application;
+                    src = ./tests/toolchains;
                   }
                   ''
                     cp -a $src/* .
+                    substituteInPlace ./build.gradle --replace-fail '@JAVA_VERSION@' '${javaVersion}'
                     env GRADLE_USER_HOME=$TMPDIR/gradle org.gradle.native.dir=$TMPDIR/native \
-                      gradle javaToolchains --no-daemon --quiet --console plain > $out
-                    cat $out | grep "Language Version:   11"
-                    cat $out | grep "Detected by:        environment variable 'JAVA_TOOLCHAIN_NIX_0'"
-                    cat $out | grep "Language Version:   23"
-                    cat $out | grep "Detected by:        environment variable 'JAVA_TOOLCHAIN_NIX_1'"
+                    gradle run --no-daemon --quiet --console plain > $out
+                    test "$(<$out)" = "${javaVersion}"
                   '';
             } // gradle.tests;
           }

pkgs/development/tools/build-managers/gradle/tests/toolchains/build.gradle

@@ -0,0 +1,11 @@
+plugins {
+    id('application')
+}
+
+java {
+    toolchain.languageVersion.set(JavaLanguageVersion.of(@JAVA_VERSION@))
+}
+
+application {
+    mainClass = 'Main'
+}

pkgs/development/tools/build-managers/gradle/tests/toolchains/src/main/java/Main.java

@@ -0,0 +1,5 @@
+public class Main {
+    public static void main(String[] args) {
+        System.out.println(System.getProperty("java.version"));
+    }
+}

pkgs/top-level/all-packages.nix

@@ -8309,7 +8309,6 @@ with pkgs;
   gnumake = callPackage ../development/tools/build-managers/gnumake { };
   gradle-packages = import ../development/tools/build-managers/gradle {
     inherit
-      jdk11
       jdk17
       jdk21
       jdk23