private static @Nullable Pair<@NotNull JpsSdk<JpsDummyElement>, @NotNull Integer> getAssociatedSdk(ModuleChunk chunk) {
    // assuming all modules in the chunk have the same associated JDK;
    // this constraint should be validated on build start
    final JpsSdk<JpsDummyElement> sdk = chunk.representativeTarget().getModule().getSdk(JpsJavaSdkType.INSTANCE);
    return sdk != null ? Pair.create(sdk, JpsJavaSdkType.getJavaVersion(sdk)) : null;
  }
private static @Nullable Pair<@NotNull JpsSdk<JpsDummyElement>, @NotNull Integer> getAssociatedSdk(ModuleChunk chunk)