code: @Override
      public byte[] transform(ClassLoader loader,
                              String className,
                              Class<?> classBeingRedefined,
                              ProtectionDomain protectionDomain,
                              byte[] classfileBuffer) throws IllegalClassFormatException {
          if (detailedTransformTrace && tc.isEntryEnabled())
              Tr.entry(this, tc, "transform", loader, className, classBeingRedefined, protectionDomain);
  
          byte[] newClassBytes = null;
          if (isTransformPossible(classfileBuffer)) {
              boolean traceEnabledForClass = injectAtTransform;
              if (!injectAtTransform && classBeingRedefined != null) {
                  WeakReference<TraceComponent> tcReference = traceComponentByClass.get(classBeingRedefined);
                  TraceComponent traceComponent = tcReference == null ? null : tcReference.get();
                  traceEnabledForClass |= (traceComponent != null && traceComponent.isEntryEnabled());
              }
              if (traceEnabledForClass) {
                  try {
                      newClassBytes = transform(classfileBuffer);
                  } catch (Throwable t) {
                      Tr.error(tc, "INSTRUMENTATION_TRANSFORM_FAILED_FOR_CLASS_2", className, t);
                  }
              }
          }
  
          if (detailedTransformTrace && tc.isEntryEnabled())
              Tr.exit(this, tc, "transform", newClassBytes);
          return newClassBytes;
      }
docs: {@inheritDoc} <p>
  This method will only execute a transformation if we're configured to class
  has been explicitly targeted for injection by {@link #traceStateChanged} or
  if we're forced to perform transformation against all classes at class
  definition because the host JVM doesn't support class retransformation or
  class redefinition.