The Greeks used to say of an uncultured person: ‘He can neither read nor swim’; today we should add: ‘nor use a computer’.
Primo Levi and Tullio Regge, Dialogue, 1984
You can locate the jar for the Base64 class (for example) with the following code:
System.out.println(Base64.class.getProtectionDomain().getCodeSource().getLocation());