question: public static String sanitizeIdentifierName ( String input ) { if ( input == null || input . isEmpty ( ) ) { return input ; } final StringBuilder result = new StringBuilder ( ) ; char ch = input . charAt ( 0 ) ; if ( Character . isJavaIdentifierStart ( ch ) ) { result . append ( ch ) ; } else { result . append ( "_" + Character . codePointAt ( input , 0 ) + "$" ) ; } int i = 1 ; while ( i < input . length ( ) ) { ch = input . charAt ( i ) ; if ( Character . isJavaIdentifierPart ( ch ) ) { result . append ( ch ) ; } else { result . append ( "_" + Character . codePointAt ( input , i ) + "$" ) ; } i = i + 1 ; } return result . toString ( ) ; }
target:  Escapes illegal characters in given identifier. Used for function names, etc.