I want to convert a pdf file to a txt file, if acrobat SDK can do it

Could you please go through below points and help me understand how can I proceed further.

1) We've Acrobat Adobe Pro tool which is used to convert pdf files of any format(encrypted, protected) into PLAIN readable pdf files.

2) And then we will use these readable pdf files as inputs to our java programs and extract the content from them.

3) When I use our JAVA program to extract the content from these kind of encrypted PDF files, we're getting the output text in symbols and non recognized fonts. So I hope if I use your "SDK\Library\jar" while extracting the content from PDF files, I'll get the content in readable text format. Even when I'm copying the content from pdf and pasting in a text file, the same thing is happening, the pasted content will have symbols and non recognized fonts.

4) We'd be happy if you can let us know about the SDK\Library\jar  which Acrobat Adobe PRO is using to convert these encrypted PDF files into PLAIN PDF files, so that we can use the same library in our JAVA programs to convert the encrypted PDF files into plain PDF files and then extract the content in text format.

5) I can see SDK in JAVASCRIPT here "https://www.adobe.com/devnet/acrobat/sdk/eula.html", but could not find it in JAVA. Also, I’m not sure whether this will be useful to meet my requirement.

Requesting your assistance at the earliest possible, as it’s very urgent. Thanks in advance