[GR-42804] Disallow System.err in c.o.svm.(core|hosted).

substratevm/src/com.oracle.graal.pointsto.standalone/src/com/oracle/graal/pointsto/standalone/PointsToAnalyzer.java

@@ -306,8 +306,8 @@ public static void main(String[] args) {
     }
 
     protected static void reportException(Throwable e) {
-        System.err.print("Exception:");
-        e.printStackTrace();
+        System.out.print("Exception:");
+        e.printStackTrace(System.out);
     }
 
     public ClassLoader getClassLoader() {

substratevm/src/com.oracle.graal.pointsto/src/com/oracle/graal/pointsto/meta/AnalysisType.java

@@ -449,7 +449,7 @@ public static boolean verifyAssignableTypes(BigBang bb) {
             }
         });
         if (!mismatchedAssignableResults.isEmpty()) {
-            mismatchedAssignableResults.forEach(System.err::println);
+            mismatchedAssignableResults.forEach(System.out::println);
             throw new AssertionError("Verification of all-instantiated type flows failed");
         }
         return true;
@@ -1166,7 +1166,7 @@ public boolean isLocal() {
         try {
             return wrapped.isLocal();
         } catch (InternalError e) {
-            System.err.println("warning: unknown locality of class " + wrapped.getName() + ", assuming class is not local. To remove the warning report an issue " +
+            System.out.println("Warning: unknown locality of class " + wrapped.getName() + ", assuming class is not local. To remove the warning report an issue " +
                             "to the library or language author. The issue is caused by " + wrapped.getName() + " which is not following the naming convention.");
             return false;
         }

substratevm/src/com.oracle.objectfile/src/com/oracle/objectfile/pecoff/PECoffUserDefinedSection.java

@@ -185,6 +185,6 @@ public void markRelocationSite(int offset, ByteBuffer bb, ObjectFile.RelocationK
      * @param msg warning message that is printed.
      */
     private static void warn(String msg) {
-        System.err.println("Warning: " + msg);
+        System.out.println("Warning: " + msg);
     }
 }

substratevm/src/com.oracle.svm.agent/src/com/oracle/svm/agent/NativeImageAgent.java

@@ -402,7 +402,9 @@ protected int onLoadCallback(JNIJavaVM vm, JvmtiEnv jvmti, JvmtiEventCallbacks c
     }
 
     private static void inform(String message) {
+        // Checkstyle: allow System.err
         System.err.println(AGENT_NAME + ": " + message);
+        // Checkstyle: disallow System.err
     }
 
     private static void warn(String message) {

substratevm/src/com.oracle.svm.configure/src/com/oracle/svm/configure/ConfigurationTool.java

@@ -116,7 +116,7 @@ public static void main(String[] args) {
                     throw new UsageException("Unknown subcommand: " + first);
             }
         } catch (UsageException e) {
-            System.err.println(e.getMessage() + System.lineSeparator() +
+            System.out.println(e.getMessage() + System.lineSeparator() +
                             "Use 'native-image-configure help' for usage.");
             System.exit(2);
         } catch (Exception e) {
@@ -311,7 +311,7 @@ private static void generate(Iterator<String> argsIter, boolean acceptTraceFileA
         }
 
         if (outputCollection.isEmpty()) {
-            System.err.println("Warning: no outputs specified, validating inputs only.");
+            System.out.println("Warning: no outputs specified, validating inputs only.");
         }
         for (URI uri : outputCollection.getReflectConfigPaths()) {
             try (JsonWriter writer = new JsonWriter(Paths.get(uri))) {

substratevm/src/com.oracle.svm.configure/src/com/oracle/svm/configure/filters/ModuleFilterTools.java

@@ -58,7 +58,7 @@ public static HierarchyFilterNode generateFromModules(String[] moduleNames, Incl
     private static void checkDependencies(Module module, Set<String> includedModuleNames) {
         for (ModuleDescriptor.Requires require : module.getDescriptor().requires()) {
             if (!includedModuleNames.contains(require.name())) {
-                System.err.println("Warning: dependency missing from input set of modules: " + module.getName() + " -> " + require.name());
+                System.out.println("Warning: dependency missing from input set of modules: " + module.getName() + " -> " + require.name());
                 checkDependencies(module.getLayer().findModule(require.name()).get(), includedModuleNames);
             }
         }

substratevm/src/com.oracle.svm.configure/src/com/oracle/svm/configure/trace/AbstractProcessor.java

@@ -42,7 +42,7 @@ void setInLivePhase(@SuppressWarnings("unused") boolean live) {
     }
 
     static void logWarning(String warning) {
-        System.err.println("Warning: " + warning);
+        System.out.println("Warning: " + warning);
     }
 
     @SuppressWarnings("unchecked")

substratevm/src/com.oracle.svm.configure/src/com/oracle/svm/configure/trace/ReflectionProcessor.java

@@ -271,7 +271,7 @@ public void processEntry(EconomicMap<String, ?> entry, ConfigurationSet configur
                 break;
             }
             default:
-                System.err.println("Unsupported reflection method: " + function);
+                System.out.println("Unsupported reflection method: " + function);
         }
     }
 

substratevm/src/com.oracle.svm.core/.checkstyle_checks.xml

@@ -54,6 +54,21 @@
       <metadata name="com.atlassw.tools.eclipse.checkstyle.comment" value="Disable Class.getSimpleName calls"/>
     </module>
 
+    <module name="RegexpSinglelineJava">
+      <property name="id" value="systemErr"/>
+      <metadata name="net.sf.eclipsecs.core.comment" value="Disallow calls to System.err."/>
+      <property name="severity" value="error"/>
+      <property name="format" value="System\.err"/>
+      <property name="message" value="Calls to System.err are restricted. Please use logging or System.out instead. (Use &quot;// Checkstyle: allow System.err ... // Checkstyle: disallow System.err&quot; to disable this check.)"/>
+      <property name="ignoreComments" value="true"/>
+    </module>
+    <module name="SuppressionCommentFilter">
+      <property name="offCommentFormat" value="Checkstyle: allow System.err"/>
+      <property name="onCommentFormat" value="Checkstyle: disallow System.err"/>
+      <property name="idFormat" value="systemErr"/>
+      <metadata name="com.atlassw.tools.eclipse.checkstyle.comment" value="Disable System.err calls"/>
+    </module>
+
     <module name="AvoidStarImport">
       <property name="allowClassImports" value="false"/>
       <property name="allowStaticMemberImports" value="false"/>

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/FallbackExecutor.java

@@ -135,7 +135,7 @@ private static Path getJavaExecutable() {
     }
 
     private static void showError(String s) {
-        System.err.println("Error: " + s);
+        System.out.println("Error: " + s);
         System.exit(1);
     }
 }

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/JavaMainWrapper.java

@@ -147,7 +147,7 @@ private static int runCore0() {
                     System.out.println("Heap dump created at '" + absoluteHeapDumpPath + "'.");
                     return 0;
                 } else {
-                    System.err.println("Unable to dump heap. Heap dumping is only supported for native executables built with `" + VMInspectionOptions.getHeapdumpsCommandArgument() + "`.");
+                    System.out.println("Unable to dump heap. Heap dumping is only supported for native executables built with `" + VMInspectionOptions.getHeapdumpsCommandArgument() + "`.");
                     return 1;
                 }
             }

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/configure/ConfigurationParser.java

@@ -130,7 +130,7 @@ protected void warnOrFail(String message) {
         if (strictConfiguration) {
             throw new JSONParserException(message);
         } else {
-            System.err.println("Warning: " + message);
+            System.out.println("Warning: " + message);
         }
     }
 

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/configure/ReflectionConfigurationParser.java

@@ -291,6 +291,6 @@ private static void handleError(String msg, Throwable cause) {
         if (cause != null) {
             message += " Reason: " + formatError(cause) + '.';
         }
-        System.err.println("Warning: " + message);
+        System.out.println("Warning: " + message);
     }
 }

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/graal/snippets/CEntryPointSnippets.java

@@ -344,8 +344,8 @@ private static int initializeIsolate(CEntryPointCreateIsolateParameters paramete
         try {
             RuntimeSupport.executeInitializationHooks();
         } catch (Throwable t) {
-            System.err.println("Uncaught exception while running initialization hooks:");
-            t.printStackTrace();
+            System.out.println("Uncaught exception while running initialization hooks:");
+            t.printStackTrace(System.out);
             CEntryPointActions.leaveTearDownIsolate();
             return CEntryPointErrors.ISOLATE_INITIALIZATION_FAILED;
         }

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/hub/ClassLoadingExceptionSupport.java

@@ -69,7 +69,7 @@ public static Throwable getExceptionForClass(String className, Throwable origina
     }
 
     private static void terminateUnconfigured(String className) {
-        System.err.println("Missing metadata error: Unable to process Class.forName invocation for class name " + className);
+        System.out.println("Missing metadata error: Unable to process Class.forName invocation for class name " + className);
         System.exit(EXIT_CODE);
     }
 }

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/jdk/TimeZoneSubstitutions.java

@@ -146,7 +146,7 @@ protected void onValueUpdate(EconomicMap<OptionKey<?>, Object> values, String ol
         };
 
         private static void printWarning() {
-            System.err.println("-H:IncludeAllTimeZones and -H:IncludeTimeZones are now deprecated. Native-image includes all timezones" +
+            System.out.println("-H:IncludeAllTimeZones and -H:IncludeTimeZones are now deprecated. Native-image includes all timezones" +
                             " by default.");
         }
     }

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/jfr/JfrFeature.java

@@ -115,7 +115,7 @@ public static boolean isInConfiguration(boolean allowPrinting) {
         boolean runtimeEnabled = VMInspectionOptions.hasJfrSupport();
         if (HOSTED_ENABLED && !runtimeEnabled) {
             if (allowPrinting) {
-                System.err.println("Warning: When FlightRecoder is used to profile the image generator, it is also automatically enabled in the native image at run time. " +
+                System.out.println("Warning: When FlightRecoder is used to profile the image generator, it is also automatically enabled in the native image at run time. " +
                                 "This can affect the measurements because it can can make the image larger and image build time longer.");
             }
             runtimeEnabled = true;

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/option/SubstrateOptionsParser.java

@@ -107,7 +107,7 @@ public static boolean parseHostedOption(String optionPrefix, EconomicMap<String,
             if (deprecationMessage != null && !deprecationMessage.isEmpty()) {
                 message += ": " + deprecationMessage;
             }
-            System.err.println(message);
+            System.out.println(message);
         }
         return true;
     }

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/reflect/proxy/DynamicProxySupport.java

@@ -133,7 +133,7 @@ public void addProxyClass(Class<?>... interfaces) {
 
                 return clazz;
             } catch (Throwable t) {
-                System.err.println("Warning: Could not create a proxy class from list of interfaces: " + Arrays.toString(interfaces) + ". Reason: " + t.getMessage());
+                System.out.println("Warning: Could not create a proxy class from list of interfaces: " + Arrays.toString(interfaces) + ". Reason: " + t.getMessage());
                 return t;
             }
         });

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/thread/JavaThreads.java

@@ -237,8 +237,8 @@ public static void dispatchUncaughtException(Thread thread, Throwable throwable)
             }
         } else {
             /* If no uncaught exception handler is present, then just report the throwable. */
-            System.err.print("Exception in thread \"" + Thread.currentThread().getName() + "\" ");
-            throwable.printStackTrace();
+            System.out.print("Exception in thread \"" + Thread.currentThread().getName() + "\" ");
+            throwable.printStackTrace(System.out);
         }
     }
 

substratevm/src/com.oracle.svm.diagnosticsagent/src/com/oracle/svm/diagnosticsagent/NativeImageDiagnosticsAgent.java

@@ -191,7 +191,7 @@ private void onClassPrepareCallback(JvmtiEnv jvmti, JNIEnvironment jni, JNIObjec
                     clinitClassMap.put(clinitMethodId.rawValue(), classHandleHolder);
                     check(jvmti.getFunctions().SetBreakpoint().invoke(jvmti, clinitMethodId, 0L));
                 } else {
-                    System.err.println("Trace class initialization requested for " + className + " but the class has not been instrumented with <clinit>.");
+                    System.out.println("Trace class initialization requested for " + className + " but the class has not been instrumented with <clinit>.");
                 }
             }
             if (advisor.shouldTraceObjectInstantiation(className)) {
@@ -211,7 +211,7 @@ private void setConstructorBreakpointsForClass(JvmtiEnv jvmti, JNIEnvironment jn
             }
         } else {
             /* This should never happen. */
-            System.err.println("Trace object instantiation requested for " + className + " but the class has no constructors.");
+            System.out.println("Trace object instantiation requested for " + className + " but the class has no constructors.");
         }
     }
 
@@ -396,8 +396,8 @@ private byte[] maybeInstrumentClassWithClinit(String clazzName, byte[] clazzData
             return writer.toByteArray();
         } catch (Throwable e) {
             String targetClazzName = clazzName != null ? clazzName : "<unknown class>";
-            System.err.println("[native-image-diagnostics-agent] Failed to instrument class " + targetClazzName + ": ");
-            e.printStackTrace(System.err);
+            System.out.println("[native-image-diagnostics-agent] Failed to instrument class " + targetClazzName + ": ");
+            e.printStackTrace(System.out);
             return null;
         }
     }

substratevm/src/com.oracle.svm.driver/src/com/oracle/svm/driver/NativeImage.java

@@ -1415,10 +1415,10 @@ private static void performBuild(BuildConfiguration config, Function<BuildConfig
         try {
             build(config, nativeImageProvider);
         } catch (NativeImageError e) {
-            NativeImage.show(System.err::println, "Error: " + e.getMessage());
+            NativeImage.show(System.out::println, "Error: " + e.getMessage());
             Throwable cause = e.getCause();
             while (cause != null) {
-                NativeImage.show(System.err::println, "Caused by: " + cause);
+                NativeImage.show(System.out::println, "Caused by: " + cause);
                 cause = cause.getCause();
             }
             if (config.getBuildArgs().contains("--verbose")) {
@@ -1734,7 +1734,7 @@ void showMessagePart(String message) {
     }
 
     public static void showWarning(String message) {
-        show(System.err::println, "Warning: " + message);
+        show(System.out::println, "Warning: " + message);
     }
 
     @SuppressWarnings("serial")

substratevm/src/com.oracle.svm.hosted/.checkstyle_checks.xml

@@ -20,6 +20,21 @@
       <metadata name="com.atlassw.tools.eclipse.checkstyle.comment" value="Disable Class.getSimpleName calls"/>
     </module>
 
+    <module name="RegexpSinglelineJava">
+      <property name="id" value="systemErr"/>
+      <metadata name="net.sf.eclipsecs.core.comment" value="Disallow calls to System.err."/>
+      <property name="severity" value="error"/>
+      <property name="format" value="System\.err"/>
+      <property name="message" value="Calls to System.err are restricted. Please use logging or System.out instead. (Use &quot;// Checkstyle: allow System.err ... // Checkstyle: disallow System.err&quot; to disable this check.)"/>
+      <property name="ignoreComments" value="true"/>
+    </module>
+    <module name="SuppressionCommentFilter">
+      <property name="offCommentFormat" value="Checkstyle: allow System.err"/>
+      <property name="onCommentFormat" value="Checkstyle: disallow System.err"/>
+      <property name="idFormat" value="systemErr"/>
+      <metadata name="com.atlassw.tools.eclipse.checkstyle.comment" value="Disable System.err calls"/>
+    </module>
+
     <module name="AvoidStarImport">
       <property name="allowClassImports" value="false"/>
       <property name="allowStaticMemberImports" value="false"/>

substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/ConfigurationTypeResolver.java

@@ -53,7 +53,7 @@ private Class<?> resolveType(String typeName, boolean warn) {
         }
         TypeResult<Class<?>> typeResult = classLoader.findClass(name);
         if (warn && !typeResult.isPresent()) {
-            System.err.println("Warning: Could not resolve " + name + " for " + configurationType + ".");
+            System.out.println("Warning: Could not resolve " + name + " for " + configurationType + ".");
         }
         return typeResult.get();
     }

substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/DeadlockWatchdog.java

@@ -76,19 +76,19 @@ void watchdogThread() {
         while (!stopped) {
             long now = System.currentTimeMillis();
             if (enabled && now >= nextDeadline) {
-                System.err.println();
-                System.err.println("=== Image generator watchdog detected no activity. This can be a sign of a deadlock during image building. Dumping all stack traces. Current time: " + new Date());
+                System.out.println();
+                System.out.println("=== Image generator watchdog detected no activity. This can be a sign of a deadlock during image building. Dumping all stack traces. Current time: " + new Date());
                 threadDump();
                 Runtime runtime = Runtime.getRuntime();
                 final long heapSizeUnit = 1024 * 1024;
                 long usedHeapSize = runtime.totalMemory() / heapSizeUnit;
                 long freeHeapSize = runtime.freeMemory() / heapSizeUnit;
                 long maximumHeapSize = runtime.maxMemory() / heapSizeUnit;
-                System.err.printf("=== Memory statistics (in MB):%n=== Used heap size: %d%n=== Free heap size: %d%n=== Maximum heap size: %d%n", usedHeapSize, freeHeapSize, maximumHeapSize);
-                System.err.flush();
+                System.out.printf("=== Memory statistics (in MB):%n=== Used heap size: %d%n=== Free heap size: %d%n=== Maximum heap size: %d%n", usedHeapSize, freeHeapSize, maximumHeapSize);
+                System.out.flush();
 
                 if (watchdogExitOnTimeout) {
-                    System.err.println("=== Image generator watchdog is aborting image generation. To configure the watchdog, use the options " +
+                    System.out.println("=== Image generator watchdog is aborting image generation. To configure the watchdog, use the options " +
                                     SubstrateOptionsParser.commandArgument(SubstrateOptions.DeadlockWatchdogInterval, Integer.toString(watchdogInterval), null) + " and " +
                                     SubstrateOptionsParser.commandArgument(SubstrateOptions.DeadlockWatchdogExitOnTimeout, "+", null));
                     /*
@@ -125,7 +125,7 @@ private static void threadDump() {
             printThreadInfo(ti);
             printLockInfo(ti.getLockedSynchronizers());
         }
-        System.err.println();
+        System.out.println();
     }
 
     private static void printThreadInfo(ThreadInfo ti) {
@@ -139,33 +139,33 @@ private static void printThreadInfo(ThreadInfo ti) {
         if (ti.isInNative()) {
             sb.append(" (running in native)");
         }
-        System.err.println(sb.toString());
+        System.out.println(sb.toString());
 
         if (ti.getLockOwnerName() != null) {
-            System.err.println("      owned by " + ti.getLockOwnerName() + " Id=" + ti.getLockOwnerId());
+            System.out.println("      owned by " + ti.getLockOwnerName() + " Id=" + ti.getLockOwnerId());
         }
 
         StackTraceElement[] stacktrace = ti.getStackTrace();
         MonitorInfo[] monitors = ti.getLockedMonitors();
         for (int i = 0; i < stacktrace.length; i++) {
             StackTraceElement ste = stacktrace[i];
-            System.err.println("    at " + ste.toString());
+            System.out.println("    at " + ste.toString());
             for (MonitorInfo mi : monitors) {
                 if (mi.getLockedStackDepth() == i) {
-                    System.err.println("      - locked " + mi);
+                    System.out.println("      - locked " + mi);
                 }
             }
         }
-        System.err.println();
+        System.out.println();
     }
 
     private static void printLockInfo(LockInfo[] locks) {
         if (locks.length > 0) {
-            System.err.println("    Locked synchronizers: count = " + locks.length);
+            System.out.println("    Locked synchronizers: count = " + locks.length);
             for (LockInfo li : locks) {
-                System.err.println("      - " + li);
+                System.out.println("      - " + li);
             }
-            System.err.println();
+            System.out.println();
         }
     }
 }

substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/Log4ShellFeature.java

@@ -62,7 +62,7 @@ public class Log4ShellFeature implements InternalFeature {
     private static final Set<String> targetMethods = Set.of("debug", "error", "fatal", "info", "log", "trace", "warn");
 
     private static void warn(String warning) {
-        System.err.println(warning);
+        System.out.println(warning);
     }
 
     private static Optional<String> getPomVersion(Class<?> log4jClass) {