Oracle application Linux

Hi everyone,
i am automating the 10 year old oracle java application, it is showing selector error some times even after editing the selector values to some number or some *'s, still the problem continuous. i have installed the Java bridge but still i am facing problem with selector. And

when i try OCR scraping it showing OCR returned null (i mean didn’t bring the any text from the screen) even then the screen is visible and also i have scraped the screen for a particular page, some times even if we scrape it is getting the wrong text even though the text is clear and is bold. ex: Dummy User it is treating it as Da##// like that, it is not consistent. can there any limitations for the automation? like UiPath can’t do these applications etc.