Special characters are properly displayed in Eclipse but not in .jar file

Question

This is my very first question on Stackoverflow.

I have developed a tool in Eclipse that receives an Excel file (.xls) and adds the content of some cells to a JList. The problem is when exporting the project to a Runnable JAR file, as all the special characters are shown as " " in the JList. However, they are properly displayed when running the application from the IDE. Please help ^^

OS: macOS High Sierra (v.10.13.1) Eclipse: Mars.1 Release (4.5.1)

Answer 1

So far I have tried the following -

1. Run - Run Configurations - Common - Encoding - ISO-8859-1
2. Run - Debug Configurations - Common - Encoding - ISO-8859-1
3. Eclipse - Preferences - General - Workspace - Text file encoding - ISO-8859-1
4. Even I went to the Eclipse folder and modified the file called "eclipse.ini"

Answer 2

FIXED!

By adding the following line: System.setProperty("file.encoding", "ISO-8859-1");