Regex fails to capture all groups

Question

Using java.util.regex (jdk 1.6), the regular expression 201210(\\d{5,5})Test applied to the subject string 20121000002Test only captures <

Answer 1

Change the line

for(int i = 1; i<m1.groupCount(); i++){     

to

for(int i = 1; i<=m1.groupCount(); i++){      //NOTE THE = ADDED HERE    

It now works as a charm!

Answer 2

for (int i = 1; i <= m1.groupCount(); i++) { 
                   ↑
              your problem

Answer 3

m1.groupCount() returns the number of capturing groups, ie. 1 in your first case so you won't enter in this loop for(int i = 1; i<m1.groupCount(); i++)

It should be for(int i = 1; i<=m1.groupCount(); i++)

Answer 4

the regular expression "201210(\d{5,5})Test" applied to the subject string "20121000002Test" only captures group(0) and does not capture group(1)

Well I can say I didn't read the manual either but if you do it says for Matcher.groupCount()

Returns the number of capturing groups in this matcher's pattern. Group zero denotes the entire pattern by convention. It is not included in this count.

Answer 5

From java.util.regex.MatchResult.groupCount:

Group zero denotes the entire pattern by convention. It is not included in this count.

So iterate through groupCount() + 1.