bootstrap/src/main/java/com/streamsets/pipeline/BlackListURLClassLoader.java
void validateClass(String name) {
    // python scripting engine generates __*__ classes under all packages (including SDC api package)
    if (!(name.endsWith("__"))) {
      for (String blacklistedPackage : blacklistedPackages) {
        if (name.startsWith(blacklistedPackage)) {
          throw new IllegalArgumentException(String.format("Class '%s' cannot be present in %s",
            name, toString()));
        }
      }
    }
  }
void validateClass(String name) {
    // python scripting engine generates __*__ classes under all packages (including SDC api package)
    if (!(name.endsWith("__"))) {
      for (String blacklistedPackage : blacklistedPackages) {
        if (name.startsWith(blacklistedPackage)) {
          throw new IllegalArgumentException(String.format("Class '%s' cannot be present in %s",
            name, toString()));
        }
      }
    }
  }
Visible for testing only