file names : Java Glossary

• ../ ..\ ./ .\ .. / \ * [ ] { } : ? ^ | " & % : ; ' < > = + or with those strings embedded as literal filenames. These have special meaning in script languages. Obviously you must use / \ in fully qualified names and ../ in names you pass to the OS, but you don’t use them in the directory and filename pieces in the disk directory.
• ! and ` have special meaning in some Unix shells.
• lead - : the filename later could be misconstrued as an option switch.
• lead . : in Unix variants this means hidden.
• Control characters or unprintable characters.
• Filenames with spaces are a bear on the command line, requiring special quoting which often gets confused. Never use leading or trailing spaces since they are often automatically trimmed.
• $ ~ @ _ are often reserved by programmers for special meaning, especially lead or trailing. It is best to avoid casual use.
• SharePoint document libraries forbid / \ : * ? " < > | # <TAB> { } % ~ &
• To be completely safe, you would have to avoid all punctuation and non-ASCII 7 alphabetics. If you must use some punctuation the safest to use are # _ -.

Case Sensitivity

My rule of thumb is to keep all filenames lower case (easier to type), easier to remember, with the exception of the *.java and *.class files which must follow Java conventions.

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