Если вы ожидаете, что это будет работать со всеми знаками препинания, а не только с ASCII, вам нужно использовать:
String new_string = old_string.replaceAll("[\\pS\\pP]", "");
Это потому, что некоторые вещи, которые вы называете пунктуацией, на самом деле являются символами, как показывает my uniprops script :
$ uniprops - \\ . , / '#' ! '$' % ^ '&' '*' ';' : { } = _ '`' '~' '(' ')'
U+002D ‹-› \N{ HYPHEN-MINUS }:
\pP \p{Pd}
All Any ASCII Assigned Common Zyyy Dash Dash_Punctuation Pd P Gr_Base Grapheme_Base Graph GrBase Punct Pat_Syn Pattern_Syntax PatSyn PosixGraph PosixPrint PosixPunct Print Punctuation XPosixGraph XPosixPrint XPosixPunct
U+005C ‹\› \N{ REVERSE SOLIDUS }:
\pP \p{Po}
All Any ASCII Assigned Common Zyyy Po P Gr_Base Grapheme_Base Graph GrBase Other_Punctuation Punct Pat_Syn Pattern_Syntax PatSyn PosixGraph PosixPrint PosixPunct Print Punctuation XPosixGraph XPosixPrint XPosixPunct
U+002E ‹.› \N{ FULL STOP }:
\pP \p{Po}
All Any ASCII Assigned Case_Ignorable CI Common Zyyy Po P Gr_Base Grapheme_Base Graph GrBase Other_Punctuation Punct Pat_Syn Pattern_Syntax PatSyn PosixGraph PosixPrint PosixPunct Print Punctuation STerm Term Terminal_Punctuation XPosixGraph XPosixPrint XPosixPunct
U+002C ‹,› \N{ COMMA }:
\pP \p{Po}
All Any ASCII Assigned Common Zyyy Po P Gr_Base Grapheme_Base Graph GrBase Other_Punctuation Punct Pat_Syn Pattern_Syntax PatSyn PosixGraph PosixPrint PosixPunct Print Punctuation Term Terminal_Punctuation XPosixGraph XPosixPrint XPosixPunct
U+002F ‹/› \N{ SOLIDUS }:
\pP \p{Po}
All Any ASCII Assigned Common Zyyy Po P Gr_Base Grapheme_Base Graph GrBase Other_Punctuation Punct Pat_Syn Pattern_Syntax PatSyn PosixGraph PosixPrint PosixPunct Print Punctuation XPosixGraph XPosixPrint XPosixPunct
U+0023 ‹#› \N{ NUMBER SIGN }:
\pP \p{Po}
All Any ASCII Assigned Common Zyyy Po P Gr_Base Grapheme_Base Graph GrBase Other_Punctuation Punct Pat_Syn Pattern_Syntax PatSyn PosixGraph PosixPrint PosixPunct Print Punctuation XPosixGraph XPosixPrint XPosixPunct
U+0021 ‹!› \N{ EXCLAMATION MARK }:
\pP \p{Po}
All Any ASCII Assigned Common Zyyy Po P Gr_Base Grapheme_Base Graph GrBase Other_Punctuation Punct Pat_Syn Pattern_Syntax PatSyn PosixGraph PosixPrint PosixPunct Print Punctuation STerm Term Terminal_Punctuation XPosixGraph XPosixPrint XPosixPunct
U+0024 ‹$› \N{ DOLLAR SIGN }:
\pS \p{Sc}
All Any ASCII Assigned Common Zyyy Currency_Symbol Sc S Gr_Base Grapheme_Base Graph GrBase Pat_Syn Pattern_Syntax PatSyn PosixGraph PosixPrint PosixPunct Print Symbol XPosixGraph XPosixPrint XPosixPunct
U+0025 ‹%› \N{ PERCENT SIGN }:
\pP \p{Po}
All Any ASCII Assigned Common Zyyy Po P Gr_Base Grapheme_Base Graph GrBase Other_Punctuation Punct Pat_Syn Pattern_Syntax PatSyn PosixGraph PosixPrint PosixPunct Print Punctuation XPosixGraph XPosixPrint XPosixPunct
U+005E ‹^› \N{ CIRCUMFLEX ACCENT }:
\pS \p{Sk}
All Any ASCII Assigned Case_Ignorable CI Common Zyyy Dia Diacritic Sk S Gr_Base Grapheme_Base Graph GrBase Math Modifier_Symbol Pat_Syn Pattern_Syntax PatSyn PosixGraph PosixPrint PosixPunct Print Symbol XPosixGraph XPosixPrint XPosixPunct
U+0026 ‹&› \N{ AMPERSAND }:
\pP \p{Po}
All Any ASCII Assigned Common Zyyy Po P Gr_Base Grapheme_Base Graph GrBase Other_Punctuation Punct Pat_Syn Pattern_Syntax PatSyn PosixGraph PosixPrint PosixPunct Print Punctuation XPosixGraph XPosixPrint XPosixPunct
U+002A ‹*› \N{ ASTERISK }:
\pP \p{Po}
All Any ASCII Assigned Common Zyyy Po P Gr_Base Grapheme_Base Graph GrBase Other_Punctuation Punct Pat_Syn Pattern_Syntax PatSyn PosixGraph PosixPrint PosixPunct Print Punctuation XPosixGraph XPosixPrint XPosixPunct
U+003B ‹;› \N{ SEMICOLON }:
\pP \p{Po}
All Any ASCII Assigned Common Zyyy Po P Gr_Base Grapheme_Base Graph GrBase Other_Punctuation Punct Pat_Syn Pattern_Syntax PatSyn PosixGraph PosixPrint PosixPunct Print Punctuation Term Terminal_Punctuation XPosixGraph XPosixPrint XPosixPunct
U+003A ‹:› \N{ COLON }:
\pP \p{Po}
All Any ASCII Assigned Case_Ignorable CI Common Zyyy Po P Gr_Base Grapheme_Base Graph GrBase Other_Punctuation Punct Pat_Syn Pattern_Syntax PatSyn PosixGraph PosixPrint PosixPunct Print Punctuation Term Terminal_Punctuation XPosixGraph XPosixPrint XPosixPunct
U+007B ‹{› \N{ LEFT CURLY BRACKET }:
\pP \p{Ps}
All Any ASCII Assigned Bidi_M Bidi_Mirrored BidiM Common Zyyy Ps P Gr_Base Grapheme_Base Graph GrBase Open_Punctuation Punct Pat_Syn Pattern_Syntax PatSyn PosixGraph PosixPrint PosixPunct Print Punctuation XPosixGraph XPosixPrint XPosixPunct
U+007D ‹}› \N{ RIGHT CURLY BRACKET }:
\pP \p{Pe}
All Any ASCII Assigned Bidi_M Bidi_Mirrored BidiM Close_Punctuation Pe Common Zyyy P Gr_Base Grapheme_Base Graph GrBase Punct Pat_Syn Pattern_Syntax PatSyn PosixGraph PosixPrint PosixPunct Print Punctuation XPosixGraph XPosixPrint XPosixPunct
U+003D ‹=› \N{ EQUALS SIGN }:
\pS \p{Sm}
All Any ASCII Assigned Common Zyyy Sm S Gr_Base Grapheme_Base Graph GrBase Math Math_Symbol Pat_Syn Pattern_Syntax PatSyn PosixGraph PosixPrint PosixPunct Print Symbol XPosixGraph XPosixPrint XPosixPunct
U+005F ‹_› \N{ LOW LINE }:
\w \pP \p{Pc}
All Any ASCII Assigned Common Zyyy Connector_Punctuation Pc P Gr_Base Grapheme_Base Graph GrBase ID_Continue IDC Punct PerlWord PosixGraph PosixPrint PosixPunct PosixWord Print Punctuation Word XID_Continue XIDC XPosixGraph XPosixPrint XPosixPunct XPosixWord
U+0060 ‹`› \N{ GRAVE ACCENT }:
\pS \p{Sk}
All Any ASCII Assigned Case_Ignorable CI Common Zyyy Dia Diacritic Sk S Gr_Base Grapheme_Base Graph GrBase Modifier_Symbol Pat_Syn Pattern_Syntax PatSyn PosixGraph PosixPrint PosixPunct Print Symbol XPosixGraph XPosixPrint XPosixPunct
U+007E ‹~› \N{ TILDE }:
\pS \p{Sm}
All Any ASCII Assigned Common Zyyy Sm S Gr_Base Grapheme_Base Graph GrBase Math Math_Symbol Pat_Syn Pattern_Syntax PatSyn PosixGraph PosixPrint PosixPunct Print Symbol XPosixGraph XPosixPrint XPosixPunct
U+0028 ‹(› \N{ LEFT PARENTHESIS }:
\pP \p{Ps}
All Any ASCII Assigned Bidi_M Bidi_Mirrored BidiM Common Zyyy Ps P Gr_Base Grapheme_Base Graph GrBase Open_Punctuation Punct Pat_Syn Pattern_Syntax PatSyn PosixGraph PosixPrint PosixPunct Print Punctuation XPosixGraph XPosixPrint XPosixPunct
U+0029 ‹)› \N{ RIGHT PARENTHESIS }:
\pP \p{Pe}
All Any ASCII Assigned Bidi_M Bidi_Mirrored BidiM Close_Punctuation Pe Common Zyyy P Gr_Base Grapheme_Base Graph GrBase Punct Pat_Syn Pattern_Syntax PatSyn PosixGraph PosixPrint PosixPunct Print Punctuation XPosixGraph XPosixPrint XPosixPunct