diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 22695de9245..4c8b792c3ea 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -31,7 +31,7 @@ jobs:
     name: Tests with Java ${{ matrix.java }} on ${{ matrix.os }}
     strategy:
       matrix:
-        java: [17, 21]
+        java: [17, 21, 25]
         os: [ubuntu-latest]
     steps:
       - name: Checkout
diff --git a/flake.nix b/flake.nix
index 0b0e3715da0..6363b17f3ed 100644
--- a/flake.nix
+++ b/flake.nix
@@ -19,7 +19,7 @@
                 let
                   base = rec {
                     jdk =
-                      if javaVersion <= 23 then prev."jdk${toString javaVersion}"
+                      if javaVersion <= 25 then prev."jdk${toString javaVersion}"
                       else abort "Not set up yet :)";
                     maven = prev.maven.override { jdk_headless = jdk; };
                   };
@@ -187,7 +187,8 @@
                 default = jdk17;
                 jdk17 = mkShell system { javaVersion = 17; };
                 jdk21 = mkShell system { javaVersion = 21; };
-                extraChecks = mkShell system { extraChecks = true; javaVersion = 23; };
+                jdk25 = mkShell system { javaVersion = 25; };
+                extraChecks = mkShell system { extraChecks = true; javaVersion = 25; };
                 jReleaser = mkShell system { release = true; javaVersion = 21; };
               });
         in
diff --git a/src/test/java/spoon/test/ctClass/CtClassTest.java b/src/test/java/spoon/test/ctClass/CtClassTest.java
index 1cb23f8ac12..b850bea0fa0 100644
--- a/src/test/java/spoon/test/ctClass/CtClassTest.java
+++ b/src/test/java/spoon/test/ctClass/CtClassTest.java
@@ -435,7 +435,7 @@ void testLocalClassExists() {
 	}
 
 	@ExtendWith(LineSeparatorExtension.class)
-	@ModelTest(value = {"src/test/resources/ctClass/Main.java"}, complianceLevel = 25)
+	@ModelTest(value = {"src/test/resources/ctClass/Main.java"}, complianceLevel = 25, noClasspath = false)
 	public void testCompactSourceFilesAndInstanceMainMethods(@BySimpleName("Main") CtClass<?> cl) {
 		// contract: Java 25 supports compact source files and instance main methods
 		assertThat(cl).getSimpleName().isEqualTo("Main");
@@ -464,7 +464,7 @@ public Person(java.lang.String name) {
 				}
 
 				void main() {
-				    IO.println(greeting());
+				    java.lang.System.out.println(greeting());
 				}
 
 				java.lang.String greeting() {
diff --git a/src/test/resources/ctClass/Main.java b/src/test/resources/ctClass/Main.java
index 45cd985fcc9..aa26316a6f9 100644
--- a/src/test/resources/ctClass/Main.java
+++ b/src/test/resources/ctClass/Main.java
@@ -20,7 +20,7 @@ public Person(String name) {
 }
 
 void main() {
-	IO.println(greeting());
+	System.out.println(greeting());
 }
 
 String greeting() {