Another problem is that "ASCII" is meaningless beyond decimal 127. (And 127 is the DELETE character, so you can't see it.) There have been a number of different versions of "extended ASCII" assigning characters to values 128-255, but there is no one standard.
Java uses Unicode, which for the first 256 characters is the same as
ISO-8859-1.
The fact that you refer to a character at position 138 on the ASCII table suggests you're not looking at a Unicode table though, since that is an unprintable character in Unicode. A commonly-encountered impostor is
Cp-1252, the Windows nonstandard version of Latin-1. Does that table match what your "ASCII table" says?
To convert Cp-1252 values to Unicode, there are several ways. One is:
If your "ASCII table" uses some other encoding besides Cp-1252, you will need to discover what encoding it is before you can convert properly. It may be helpful to tell us what operating system you're using, and what country you're in.