feat(agent): Move forced class preload into instrumenter module

PerfectSlayer · PerfectSlayer · commit e95e91e26eb2 · 2026-04-16T10:49:54.000+02:00
diff --git a/dd-java-agent/agent-tooling/src/main/java/datadog/trace/agent/tooling/InstrumenterModule.java b/dd-java-agent/agent-tooling/src/main/java/datadog/trace/agent/tooling/InstrumenterModule.java
@@ -90,6 +90,7 @@ public int order() {
   }
 
   public List<Instrumenter> typeInstrumentations() {
+    preloadClasses();
     return singletonList(this);
   }
 
@@ -214,6 +215,28 @@ protected final boolean isShortcutMatchingEnabled(boolean defaultToShortcut) {
         .isIntegrationShortcutMatchingEnabled(singletonList(name()), defaultToShortcut);
   }
 
+  /**
+   * Force loading of classes that need to be instrumented, but are using during instrumentation.
+   */
+  @SuppressForbidden // allow this use of Class.forName()
+  protected void preloadClasses() {
+    String[] list = preloadClassNames();
+    if (list != null) {
+      for (String clazz : list) {
+        try {
+          Class.forName(clazz);
+        } catch (Throwable t) {
+          log.debug("Error force loading {} class", clazz);
+        }
+      }
+    }
+  }
+
+  /** Get classes to force load */
+  public String[] preloadClassNames() {
+    return null;
+  }
+
   /** Parent class for all tracing related instrumentations */
   public abstract static class Tracing extends InstrumenterModule {
     public Tracing(String instrumentationName, String... additionalNames) {
@@ -258,18 +281,11 @@ public final boolean isApplicable(Set<TargetSystem> enabledSystems) {
   }
 
   /** Parent class for all IAST related instrumentations */
-  @SuppressForbidden
   public abstract static class Iast extends InstrumenterModule {
     public Iast(String instrumentationName, String... additionalNames) {
       super(instrumentationName, additionalNames);
     }
 
-    @Override
-    public List<Instrumenter> typeInstrumentations() {
-      preloadClassNames();
-      return super.typeInstrumentations();
-    }
-
     @Override
     public final boolean isApplicable(Set<TargetSystem> enabledSystems) {
       if (enabledSystems.contains(TargetSystem.IAST)) {
@@ -282,27 +298,6 @@ public final boolean isApplicable(Set<TargetSystem> enabledSystems) {
       return cfg.getAppSecActivation() == ProductActivation.FULLY_ENABLED;
     }
 
-    /**
-     * Force loading of classes that need to be instrumented, but are using during instrumentation.
-     */
-    private void preloadClassNames() {
-      String[] list = getClassNamesToBePreloaded();
-      if (list != null) {
-        for (String clazz : list) {
-          try {
-            Class.forName(clazz);
-          } catch (Throwable t) {
-            log.debug("Error force loading {} class", clazz);
-          }
-        }
-      }
-    }
-
-    /** Get classes to force load* */
-    public String[] getClassNamesToBePreloaded() {
-      return null;
-    }
-
     @Override
     public Advice.PostProcessor.Factory postProcessor() {
       return IastPostProcessorFactory.INSTANCE;
diff --git a/dd-java-agent/instrumentation/java/java-io-1.8/src/main/java/datadog/trace/instrumentation/java/lang/InputStreamInstrumentation.java b/dd-java-agent/instrumentation/java/java-io-1.8/src/main/java/datadog/trace/instrumentation/java/lang/InputStreamInstrumentation.java
@@ -20,7 +20,7 @@
 public class InputStreamInstrumentation extends InstrumenterModule.Iast
     implements Instrumenter.ForTypeHierarchy, Instrumenter.HasMethodAdvice {
 
-  private static final String[] FORCE_LOADING = {"java.io.PushbackInputStream"};
+  private static final String[] PRELOAD_CLASS_NAMES = {"java.io.PushbackInputStream"};
 
   public InputStreamInstrumentation() {
     super("inputStream");
@@ -44,8 +44,8 @@ public void methodAdvice(MethodTransformer transformer) {
   }
 
   @Override
-  public String[] getClassNamesToBePreloaded() {
-    return FORCE_LOADING;
+  public String[] preloadClassNames() {
+    return PRELOAD_CLASS_NAMES;
   }
 
   public static class InputStreamAdvice {
