System.out.println(String.class.getName()+ ".class");System.out.println(String.class.getName().replaceAll(".","/") + ".class");

java.lang.String.class

java/lang/String/class

.class

 原因

        System.out.println(String.class.getName().replaceAll("\\.","/") + ".class");    

        System.out.println(String.class.getName().replaceAll("\\Q.\\E","/") + ".class");    

        System.out.println(String.class.getName().replaceAll(Pattern.quote("."),"/") + ".class");    

 /*** Returns a literal pattern <code>String</code> for the specified* <code>String</code>.** <p>This method produces a <code>String</code> that can be used to* create a <code>Pattern</code> that would match the string* <code>s</code> as if it were a literal pattern.</p> Metacharacters* or escape sequences in the input sequence will be given no special* meaning.** @param s The string to be literalized* @return A literal string replacement* @since 1.5*/public static String quote(String s) {int slashEIndex = s.indexOf("\\E");if (slashEIndex == -1)return "\\Q" + s + "\\E";StringBuilder sb = new StringBuilder(s.length() * 2);sb.append("\\Q");slashEIndex = 0;int current = 0;while ((slashEIndex = s.indexOf("\\E", current)) != -1) {sb.append(s.substring(current, slashEIndex));current = slashEIndex + 2;sb.append("\\E\\\\E\\Q");}sb.append(s.substring(current, s.length()));sb.append("\\E");return sb.toString();}

import java.util.regex.Matcher;
import java.util.regex.Pattern;public class CheckSpecialCharacterString {/*** Check whether the each character of String is special character or not using java* @author www.instanceofjava.com*/public static void main(String[] args) {
String Str="Java String interview questions*$%";String specialCharacters=" !#$%&'()*+,-./:;<=>?@[]^_`{|}";for (int i = 0; i < Str.length(); i++) {if (specialCharacters.contains(Character.toString(Str.charAt(i)))){System.out.println(Str.charAt(i)+": is a special character");} }}}