pattern.matcher() vs pattern.matches()

Solution 1:

pattern.matcher(String s) returns a Matcher that can find patterns in the String s. pattern.matches(String str) tests, if the entire String (str) matches the pattern.

In brief (just to remember the difference):

• pattern.matcher - test if the string contains-a pattern
• pattern.matches - test if the string is-a pattern

Solution 2:

Matcher.find() attempts to find the next subsequence of the input sequence that matches the pattern.

Pattern.matches(String regex, CharSequence input) compiles the regex into a Matcher and returns Matcher.matches().

Matcher.matches attempts to match the entire region (string) against the pattern (Regex).

So, in your case, the Pattern.matches("\\+", str) returns a false since str.equals("+") is false.