Only call getRuntimeMXBean if needed (#605)

classgraph · Nov 26, 2021 · c946fa9 · c946fa9
1 parent 7a66f12
commit c946fa9
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Showing 3 changed files with 39 additions and 29 deletions.
diff --git a/src/main/java/io/github/classgraph/ClassGraph.java b/src/main/java/io/github/classgraph/ClassGraph.java
@@ -1764,6 +1764,7 @@ public List<ModuleRef> getModules() {
      * @return The {@link ModulePathInfo}.
      */
     public ModulePathInfo getModulePathInfo() {
+        scanSpec.modulePathInfo.getRuntimeInfo();
         return scanSpec.modulePathInfo;
     }
 }
diff --git a/src/main/java/io/github/classgraph/ModulePathInfo.java b/src/main/java/io/github/classgraph/ModulePathInfo.java
@@ -33,6 +33,7 @@
 import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Set;
+import java.util.concurrent.atomic.AtomicBoolean;
 
 import nonapi.io.github.classgraph.reflection.ReflectionUtils;
 import nonapi.io.github.classgraph.utils.JarUtils;
@@ -126,36 +127,43 @@ public class ModulePathInfo {
             '\0' // --add-reads (only one param per switch)
     );
 
+    /** Set to true once {@link #getRuntimeInfo()} is called. */
+    private final AtomicBoolean gotRuntimeInfo = new AtomicBoolean();
+
     /** Construct a {@link ModulePathInfo}. */
-    public ModulePathInfo() {
-        // Read the raw commandline arguments to get the module path override parameters.
-        // If the java.management module is not present in the deployed runtime (for JDK 9+), or the runtime
-        // does not contain the java.lang.management package (e.g. the Android build system, which also does
-        // not support JPMS currently), then skip trying to read the commandline arguments (#404).
-        final Class<?> managementFactory = ReflectionUtils
-                .classForNameOrNull("java.lang.management.ManagementFactory");
-        final Object runtimeMXBean = managementFactory == null ? null
-                : ReflectionUtils.invokeStaticMethod(/* throwException = */ false, managementFactory,
-                        "getRuntimeMXBean");
-        @SuppressWarnings("unchecked")
-        final List<String> commandlineArguments = runtimeMXBean == null ? null
-                : (List<String>) ReflectionUtils.invokeMethod(/* throwException = */ false, runtimeMXBean,
-                        "getInputArguments");
-        if (commandlineArguments != null) {
-            for (final String arg : commandlineArguments) {
-                for (int i = 0; i < fields.size(); i++) {
-                    final String argSwitch = argSwitches.get(i);
-                    if (arg.startsWith(argSwitch)) {
-                        final String argParam = arg.substring(argSwitch.length());
-                        final Set<String> argField = fields.get(i);
-                        final char sepChar = argPartSeparatorChars.get(i);
-                        if (sepChar == '\0') {
-                            // Only one param per switch
-                            argField.add(argParam);
-                        } else {
-                            // Split arg param into parts
-                            argField.addAll(Arrays
-                                    .asList(JarUtils.smartPathSplit(argParam, sepChar, /* scanSpec = */ null)));
+    void getRuntimeInfo() {
+        // Only call this reflective method if ModulePathInfo is specifically requested, to avoid illegal
+        // access warning on some JREs, e.g. Adopt JDK 11 (#605)
+        if (!gotRuntimeInfo.getAndSet(true)) {
+            // Read the raw commandline arguments to get the module path override parameters.
+            // If the java.management module is not present in the deployed runtime (for JDK 9+), or the runtime
+            // does not contain the java.lang.management package (e.g. the Android build system, which also does
+            // not support JPMS currently), then skip trying to read the commandline arguments (#404).
+            final Class<?> managementFactory = ReflectionUtils
+                    .classForNameOrNull("java.lang.management.ManagementFactory");
+            final Object runtimeMXBean = managementFactory == null ? null
+                    : ReflectionUtils.invokeStaticMethod(/* throwException = */ false, managementFactory,
+                            "getRuntimeMXBean");
+            @SuppressWarnings("unchecked")
+            final List<String> commandlineArguments = runtimeMXBean == null ? null
+                    : (List<String>) ReflectionUtils.invokeMethod(/* throwException = */ false, runtimeMXBean,
+                            "getInputArguments");
+            if (commandlineArguments != null) {
+                for (final String arg : commandlineArguments) {
+                    for (int i = 0; i < fields.size(); i++) {
+                        final String argSwitch = argSwitches.get(i);
+                        if (arg.startsWith(argSwitch)) {
+                            final String argParam = arg.substring(argSwitch.length());
+                            final Set<String> argField = fields.get(i);
+                            final char sepChar = argPartSeparatorChars.get(i);
+                            if (sepChar == '\0') {
+                                // Only one param per switch
+                                argField.add(argParam);
+                            } else {
+                                // Split arg param into parts
+                                argField.addAll(Arrays
+                                        .asList(JarUtils.smartPathSplit(argParam, sepChar, /* scanSpec = */ null)));
+                            }
                         }
                     }
                 }

diff --git a/src/main/java/io/github/classgraph/ScanResult.java b/src/main/java/io/github/classgraph/ScanResult.java
@@ -449,6 +449,7 @@ public List<ModuleRef> getModules() {
      * @return The {@link ModulePathInfo}.
      */
     public ModulePathInfo getModulePathInfo() {
+        scanSpec.modulePathInfo.getRuntimeInfo();
         return scanSpec.modulePathInfo;
     }