code: protected void applyStamp(CtClass candidateClass) throws CannotCompileException {
      candidateClass.addField(createStampField(candidateClass), Initializer.constant(true));
    }
docs: Apply a "stamp" to a class to indicate it has been modified.
  <p>
  By default, this method uses a boolean field named {@value #STAMP_FIELD_NAME} as the stamp. Any
  class overriding this method should also override {@link #hasStamp(CtClass)}.
  </p>
  
  @param candidateClass the class to mark/stamp must not be {@code null}.
  
  @throws NullPointerException if passed {@code candidateClass} is {@code null}.
  @throws CannotCompileException by {@link CtClass#addField(CtField, CtField.Initializer)}
  
  @see #createStampField(CtClass)
  @see CtClass#addField(CtField, CtField.Initializer)