PortfoliosService portfoliosService = IntxServiceFactory.createPortfoliosService(client);
GetPositionForPortfolioInstrumentRequest request = new GetPositionForPortfolioInstrumentRequest.Builder()
    .portfolio("portfolio_id")
    .instrument("BTC-USDC")
    .build();
GetPositionForPortfolioInstrumentResponse response = portfoliosService.getPositionForPortfolioInstrument(request);

For more information, please visit the INTX Java SDK.