Java Coding Problems

Conventions used

There are a number of text conventions used throughout this book.

CodeInText: Indicates code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles. Here is an example: "If the current character exists in the Map instance, then simply increase its occurrences by 1 with (character, occurrences+1)."

A block of code is set as follows:

public Map<Character, Integer> countDuplicateCharacters(String str) {  Map<Character, Integer> result = new HashMap<>();  // or use for(char ch: str.toCharArray()) { ... }  for (int i = 0; i<str.length(); i++) {    char ch = str.charAt(i);     result.compute(ch, (k, v) -> (v == null) ? 1 : ++v);  }  return result;}

When we wish ...