update github urls from "master" to "main" (exercism#2141)

pedrobragadev · web-flow · commit 6d55852c9940 · 2022-07-17T12:15:16.000+01:00
diff --git a/.github/PULL_REQUEST_TEMPLATE.md b/.github/PULL_REQUEST_TEMPLATE.md
@@ -9,4 +9,4 @@
 
 Reviewer Resources:
 
-[Track Policies](https://github.com/exercism/java/blob/master/POLICIES.md#event-checklist)
+[Track Policies](https://github.com/exercism/java/blob/main/POLICIES.md#event-checklist)
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
@@ -27,7 +27,7 @@ For general guidelines about contributing to Exercism see the [Exercism contribu
 
 Hi! Thanks for contributing to the Exercism Java track!
 
-Before opening your pull request, please review the [track policies](https://github.com/exercism/java/blob/master/POLICIES.md) and make sure your changes comply with them all.
+Before opening your pull request, please review the [track policies](https://github.com/exercism/java/blob/main/POLICIES.md) and make sure your changes comply with them all.
 This helps us focus our review time on the more important aspects of your contributions.
 
 Also please only address one issue per pull request and reference the issue in your pull request. This makes it easier for us to review it, and it means that if we request changes to the fix for one issue, it won't prevent to a fix for another issue being merged.
@@ -48,7 +48,7 @@ To submit a fix for an existing exercise or port an exercise to Java with the le
    (see [exercism.io: Installing Java](https://exercism.org/docs/tracks/java/installation))
 -  **Setup a branch on a fork of [exercism/java](https://github.com/exercism/java) on your computer.**
 
-   See [GitHub Help: Forking](https://help.github.com/articles/fork-a-repo/).  Use those instructions (in conjunction with the [Git Basics doc](https://github.com/exercism/docs/blob/master/contributing/git-basics.md)) to:
+   See [GitHub Help: Forking](https://help.github.com/articles/fork-a-repo/).  Use those instructions (in conjunction with the [Contributing via GitHub](https://github.com/exercism/docs/tree/main/building/github#contributing-via-github)) to:
    * "fork" a repository on GitHub;
    - install `git`;
    - "clone" a copy of your fork;
@@ -164,7 +164,7 @@ The easiest way to achieve this is simply use the `bin/journey-test.sh` script.
 The easiest way to add a new exercise to the Java track is to port an exercise from another track.
 That means that you take an exercise that has already been implemented in another language and you implement it in this track.
 
-To add a completely new exercise you need to open a pull request to the [problem specifications repository](https://github.com/exercism/problem-specifications/tree/master/exercises).
+To add a completely new exercise you need to open a pull request to the [problem specifications repository](https://github.com/exercism/problem-specifications/tree/main/exercises).
 Any completely new exercise needs to be added and accepted there before it can be added to the Java track.
 
 There is a [general Exercism guide for porting an exercise to a new language](https://github.com/exercism/docs/blob/master/you-can-help/implement-an-exercise-from-specification.md).
@@ -186,7 +186,7 @@ This list is in alphabetical order so please add your exercise so that it mainta
 
 * Please add an exercise submodule for your exercise.
 See [The Problem Submodules](#the-problem-submodules) section for what needs to be in this.
-See the [POLICIES doc](https://github.com/exercism/java/blob/master/POLICIES.md#starter-implementations) for an explanation of when you need to add a starter implementation.
+See the [POLICIES doc](https://github.com/exercism/java/blob/main/POLICIES.md#starter-implementations) for an explanation of when you need to add a starter implementation.
 The `build.gradle` file can just be copied from any other exercise submodule.
 The `README.md` file can be generated using [configlet](https://github.com/exercism/configlet/releases).
 You can do this by:
@@ -203,16 +203,16 @@ If there is canonical data for your exercise then you should follow this when ma
 We aim to follow the canonical data as closely as possible in our tests to ensure thorough test coverage.
 If there is canonical data available you also need to create a file at `exercises/exercise-slug/.meta/version` specifying the canonical data version you have implemented (e.g. `1.0.0`).
 The canonical data version can be found at the top of the canonical data file for that exercise.
-See other exercises, e.g. [acronym](https://github.com/exercism/java/tree/master/exercises/acronym/.meta), for an example `version` file.
+See other exercises, e.g. [acronym](https://github.com/exercism/java/tree/main/exercises/practice/acronym/.meta), for an example `version` file.
 
-* Make sure you've followed the [track policies](https://github.com/exercism/java/blob/master/POLICIES.md), especially the ones for exercise added/updated.
+* Make sure you've followed the [track policies](https://github.com/exercism/java/blob/main/POLICIES.md), especially the ones for exercise added/updated.
 
 Hopefully that should be enough information to help you port an exercise to the Java track.
 Feel free to open an issue or post in the [Gitter exercism/java room](https://gitter.im/exercism/java) if you have any questions and we'll try and answer as soon as we can.
 
 ## Updating the READMEs
 
-The `README.md` files are generated from the exercise descriptions in [problem specifications](https://github.com/exercism/problem-specifications/tree/master/exercises).
+The `README.md` files are generated from the exercise descriptions in [problem specifications](https://github.com/exercism/problem-specifications/tree/main/exercises).
 They need to be regenerated regularly so that any changes to the descriptions in problem specifications propagate to our READMEs.
 This can be done using [configlet](https://github.com/exercism/configlet/releases):
 
@@ -224,14 +224,14 @@ This can be done using [configlet](https://github.com/exercism/configlet/release
 
 ## Checking tests are up to date
 
-The tests for each exercise should follow the canonical data in [problem specifications](https://github.com/exercism/problem-specifications/tree/master/exercises) as closely as possible.
+The tests for each exercise should follow the canonical data in [problem specifications](https://github.com/exercism/problem-specifications/tree/main/exercises) as closely as possible.
 The canonical data can change quite regularly, in which case the [canonical data version](https://github.com/exercism/problem-specifications#test-data-versioning) for that exercise will be updated.
 
-We keep track of which version of the canonical data each exercise implements in a version file, for example: https://github.com/exercism/java/blob/master/exercises/two-fer/.meta/version.
+We keep track of which version of the canonical data each exercise implements in a version file, for example: https://github.com/exercism/java/blob/main/exercises/practice/two-fer/.meta/version.
 Not all exercises have canonical data in problem specifications.
 For those that don't we don't add a version file.
 
-We have [a script](https://github.com/exercism/java/blob/master/scripts/canonical_data_check.sh) which can check if these version are up to date with the ones in problem specification.
+We have [a script](https://github.com/exercism/java/blob/main/scripts/canonical_data_check.sh) which can check if these version are up to date with the ones in problem specification.
 This script can be used to check if any version files, tests and reference implementations need updating.
 
 To run this script:
@@ -242,7 +242,7 @@ To run this script:
   
 ## Checking tests are up to date and submit new issues
 
-There is [a script which allows you to submit new issues](https://github.com/exercism/java/blob/master/scripts/create_issues_versionchange_canonical.sh) to this repo with generic title, description and labels if a change in version was detected.
+There is [a script which allows you to submit new issues](https://github.com/exercism/java/blob/main/scripts/create_issues_versionchange_canonical.sh) to this repo with generic title, description and labels if a change in version was detected.
 
 Example generic new issue:
 <img width="1005" alt="image" src="https://user-images.githubusercontent.com/6614867/57221803-bf1a6600-7000-11e9-93cf-b930ef24ce97.png">
@@ -271,7 +271,7 @@ To run this script:
 
 ## Checking exercises are implemented and submit new issues
 
-There is [a script](https://github.com/exercism/java/blob/master/scripts/create_issues_new_exercise.sh) which allows you to easily check if there are any exercism exercises which haven't been implemented in the Java track, and create issues for those exercises if there are any.
+There is [a script](https://github.com/exercism/java/blob/main/scripts/create_issues_new_exercise.sh) which allows you to easily check if there are any exercism exercises which haven't been implemented in the Java track, and create issues for those exercises if there are any.
 
 Before you may submit a new issue, the script
   1. Checks whether the exercise exists in the Java track (compared to exercism/problem-specifications)
diff --git a/POLICIES.md b/POLICIES.md
@@ -36,7 +36,7 @@ References: [[1](https://github.com/exercism/java/issues/177#issuecomment-261291
 > - Exercises of difficulty 4 or lower: provide stubs for all required constructors and methods. This means that you need to provide stubs for those constructors or methods that are necessary to pass all tests. E.g. stubs for private methods may be skipped.
 Stubs should include the following body:
     `throw new UnsupportedOperationException("Delete this statement and write your own implementation.");`
-> - Exercises of difficulty 5 or higher: copy the StubTemplate.java file (provided [here](https://github.com/exercism/java/tree/master/_template/src/main/java)) and rename it to fit the exercise. For example, for the exercise linked-list the file could be named LinkedList.java. Then either (1) add hints to the hints.md file (which gets merged into the README.md for the exercise) or (2) provide stubs as above for exercises that demand complicated method signatures.
+> - Exercises of difficulty 5 or higher: copy the StubTemplate.java file (provided [here](https://github.com/exercism/java/tree/main/_template/src/main/java)) and rename it to fit the exercise. For example, for the exercise linked-list the file could be named LinkedList.java. Then either (1) add hints to the hints.md file (which gets merged into the README.md for the exercise) or (2) provide stubs as above for exercises that demand complicated method signatures.
 
 References: [[1](https://github.com/exercism/java/issues/178)], [[2](https://github.com/exercism/java/pull/683#discussion_r125506930)], [[3](https://github.com/exercism/java/issues/977)], [[4](https://github.com/exercism/java/issues/1721)]
 
@@ -103,7 +103,7 @@ References: [[1](https://github.com/exercism/java/issues/395#issue-215734887)]
 
 > If you're testing a class called `SomeClassName` then your test class should be called `SomeClassNameTest`.
 
-> The exception to this is if the tests are split into several test classes where each test class tests different functionality. In that case each class should be named `SomeClassNameFunctionalityTest` where `Functionality` is the name of the functionality to be tested in that class. See the [clock exercise](https://github.com/exercism/java/tree/master/exercises/clock) as an example.
+> The exception to this is if the tests are split into several test classes where each test class tests different functionality. In that case each class should be named `SomeClassNameFunctionalityTest` where `Functionality` is the name of the functionality to be tested in that class. See the [clock exercise](https://github.com/exercism/java/tree/main/exercises/practice/clock) as an example.
 
 References: [[1](https://github.com/exercism/java/issues/697)]
 
@@ -115,7 +115,7 @@ References: [[1](https://github.com/exercism/java/issues/697)]
 
 > Therefore a hints.md file should be added to the .meta directory for every exercise with difficulty 5.
 > This file should explain what they need to do when there is no starter implementation.
-> The files should all be the same so you can copy it from any other exercise with difficulty 5, e.g. [flatten-array](https://github.com/exercism/java/tree/master/exercises/flatten-array/.meta/hints.md).
+> The files should all be the same so you can copy it from any other exercise with difficulty 5, e.g. [flatten-array](https://github.com/exercism/java/tree/main/exercises/pratice/flatten-array/.meta/hints.md).
 
 > We add the file to every exercise with difficulty 5 because the structure of the track means that we don't know which exercise will be the first one without starter implementation that a user will be faced with.
 
@@ -131,7 +131,7 @@ References: [[1](https://github.com/exercism/java/issues/1389)]
 
 ### Avoid returning null
 
-> The [canonical data](https://github.com/exercism/problem-specifications/tree/master/exercises) for each exercise intentionally doesn't deal with error handling.
+> The [canonical data](https://github.com/exercism/problem-specifications/tree/main/exercises) for each exercise intentionally doesn't deal with error handling.
 > When an error has occured or a method can't return anything, the canonical data will just mark that as `"expected": null`.
 > This is because error handling varies from language to language, so the canonical data is leaving it up to each language track to decide how to deal with those situations.
 > It doesn't mean that the method needs to return `null`.
@@ -141,11 +141,11 @@ References: [[1](https://github.com/exercism/java/issues/1389)]
 
 > It's considered best practice to deal with errors and unexpected circumstances by throwing exceptions.
 > If you throw an exception then you force the user to deal with the problem.
-> You can either define your own exception (see [the triangle exercise](https://github.com/exercism/java/blob/master/exercises/triangle/.meta/src/reference/java/TriangleException.java) for an example) or use a predefined one (see [the collatz-conjecture exercise](https://github.com/exercism/java/blob/master/exercises/collatz-conjecture/src/test/java/CollatzCalculatorTest.java) for an example).
+> You can either define your own exception (see [the triangle exercise](https://github.com/exercism/java/blob/main/exercises/practice/triangle/.meta/src/reference/java/TriangleException.java) for an example) or use a predefined one (see [the collatz-conjecture exercise](https://github.com/exercism/java/blob/main/exercises/practice/collatz-conjecture/src/test/java/CollatzCalculatorTest.java) for an example).
 
 > Another option is to use [Optionals](https://docs.oracle.com/javase/8/docs/api/java/util/Optional.html).
 > This can be more suitable if the case you want to deal with isn't an exceptional occurence, but rather an expected scenario, e.g. a search method not finding what it was searching for.
-> See [the word-search exercise](https://github.com/exercism/java/blob/master/exercises/word-search/src/test/java/WordSearcherTest.java) for an example where `Optional` is used.
+> See [the word-search exercise](https://github.com/exercism/java/blob/main/exercises/practice/word-search/src/test/java/WordSearcherTest.java) for an example where `Optional` is used.
 
 References: [[1](https://www.codebyamir.com/blog/stop-returning-null-in-java)]
 
@@ -159,7 +159,7 @@ References: [[1](https://www.codebyamir.com/blog/stop-returning-null-in-java)]
 > Furthermore, you can make assertions on the state of a domain object after the exception has been thrown.
 > To be consistent, please use `assertThrows` whenever you expect an exception to be thrown.
 
-> See [the triangle tests](https://github.com/exercism/java/blob/master/exercises/triangle/src/test/java/TriangleTest.java) for an example of where `assertThrows` is used.
+> See [the triangle tests](https://github.com/exercism/java/blob/main/exercises/practice/triangle/src/test/java/TriangleTest.java) for an example of where `assertThrows` is used.
 
 References: [[1](https://github.com/junit-team/junit4/wiki/Exception-testing)]
 
diff --git a/README.md b/README.md
@@ -8,4 +8,4 @@ Source for Exercism Exercises in Java.
 
 For general information about how to contribute to Exercism, please refer to the [Contributing Guide](https://exercism.org/contributing).
 
-For information on contributing to this track, refer to the [CONTRIBUTING.md](https://github.com/exercism/java/blob/master/CONTRIBUTING.md) file.
+For information on contributing to this track, refer to the [CONTRIBUTING.md](https://github.com/exercism/java/blob/main/CONTRIBUTING.md) file.
diff --git a/exercises/practice/flatten-array/.meta/hints.md b/exercises/practice/flatten-array/.meta/hints.md
@@ -0,0 +1,57 @@
+Since this exercise has difficulty 5 it doesn't come with any starter implementation.
+This is so that you get to practice creating classes and methods which is an important part of programming in Java.
+It does mean that when you first try to run the tests, they won't compile.
+They will give you an error similar to:
+```
+ path-to-exercism-dir\exercism\java\name-of-exercise\src\test\java\ExerciseClassNameTest.java:14: error: cannot find symbol
+        ExerciseClassName exerciseClassName = new ExerciseClassName();
+        ^
+ symbol:   class ExerciseClassName
+ location: class ExerciseClassNameTest
+```
+This error occurs because the test refers to a class that hasn't been created yet (`ExerciseClassName`).
+To resolve the error you need to add a file matching the class name in the error to the `src/main/java` directory.
+For example, for the error above you would add a file called `ExerciseClassName.java`.
+
+When you try to run the tests again you will get slightly different errors.
+You might get an error similar to:
+```
+  constructor ExerciseClassName in class ExerciseClassName cannot be applied to given types;
+        ExerciseClassName exerciseClassName = new ExerciseClassName("some argument");
+                                              ^
+  required: no arguments
+  found: String
+  reason: actual and formal argument lists differ in length
+```
+This error means that you need to add a [constructor](https://docs.oracle.com/javase/tutorial/java/javaOO/constructors.html) to your new class.
+If you don't add a constructor, Java will add a default one for you.
+This default constructor takes no arguments.
+So if the tests expect your class to have a constructor which takes arguments, then you need to create this constructor yourself.
+In the example above you could add:
+```
+ExerciseClassName(String input) {
+}
+``` 
+That should make the error go away, though you might need to add some more code to your constructor to make the test pass!
+
+You might also get an error similar to:
+```
+  error: cannot find symbol
+        assertEquals(expectedOutput, exerciseClassName.someMethod());
+                                                       ^
+  symbol:   method someMethod()
+  location: variable exerciseClassName of type ExerciseClassName
+```
+This error means that you need to add a method called `someMethod` to your new class.
+In the example above you would add:
+```
+String someMethod() {
+  return "";
+}
+```
+Make sure the return type matches what the test is expecting.
+You can find out which return type it should have by looking at the type of object it's being compared to in the tests.
+Or you could set your method to return some random type (e.g. `void`), and run the tests again.
+The new error should tell you which type it's expecting.
+
+After having resolved these errors you should be ready to start making the tests pass!
diff --git a/exercises/practice/hello-world/.docs/instructions.append.md b/exercises/practice/hello-world/.docs/instructions.append.md
@@ -138,4 +138,4 @@ The entire of Exercism is Open Source and is a labor of love for over
 
 A starting point to jumping in can be found here:
 
-https://github.com/exercism/docs/tree/master/contributing-to-language-tracks
+https://github.com/exercism/docs/tree/main/building
diff --git a/reference/exercise-concepts/gigasecond.md b/reference/exercise-concepts/gigasecond.md
@@ -1,6 +1,6 @@
 # Gigasecond
 
-[Example implementation](https://github.com/exercism/java/blob/master/exercises/gigasecond/.meta/src/reference/java/Gigasecond.java)
+[Example implementation](https://github.com/exercism/java/blob/main/exercises/practice/gigasecond/.meta/src/reference/java/Gigasecond.java)
 
 ## General
 
diff --git a/reference/exercise-concepts/leap.md b/reference/exercise-concepts/leap.md
@@ -2,7 +2,7 @@
 
 #Leap
 
-[Example implementation](https://github.com/exercism/java/blob/master/exercises/leap/.meta/src/reference/java/Leap.java)
+[Example implementation](https://github.com/exercism/java/blob/main/exercises/practice/leap/.meta/src/reference/java/Leap.java)
 
 ## General
 
diff --git a/reference/exercise-concepts/matrix.md b/reference/exercise-concepts/matrix.md
diff --git a/reference/exercise-concepts/rna-transcription.md b/reference/exercise-concepts/rna-transcription.md
diff --git a/scripts/create_issues_new_exercise.sh b/scripts/create_issues_new_exercise.sh
diff --git a/scripts/create_issues_versionchange_canonical.sh b/scripts/create_issues_versionchange_canonical.sh

Original file line number	Diff line number	Diff line change
`@@ -9,4 +9,4 @@`
`9`	`9`
`10`	`10`	`Reviewer Resources:`
`11`	`11`
`12`		`-[Track Policies](https://github.com/exercism/java/blob/master/POLICIES.md#event-checklist)`
	`12`	`+[Track Policies](https://github.com/exercism/java/blob/main/POLICIES.md#event-checklist)`
Original file line number	Diff line number	Diff line change
`@@ -8,4 +8,4 @@ Source for Exercism Exercises in Java.`
`8`	`8`
`9`	`9`	`For general information about how to contribute to Exercism, please refer to the [Contributing Guide](https://exercism.org/contributing).`
`10`	`10`
`11`		`-For information on contributing to this track, refer to the [CONTRIBUTING.md](https://github.com/exercism/java/blob/master/CONTRIBUTING.md) file.`
	`11`	`+For information on contributing to this track, refer to the [CONTRIBUTING.md](https://github.com/exercism/java/blob/main/CONTRIBUTING.md) file.`
Original file line number	Diff line number	Diff line change
`@@ -138,4 +138,4 @@ The entire of Exercism is Open Source and is a labor of love for over`
`138`	`138`
`139`	`139`	`A starting point to jumping in can be found here:`
`140`	`140`
`141`		`-https://github.com/exercism/docs/tree/master/contributing-to-language-tracks`
	`141`	`+https://github.com/exercism/docs/tree/main/building`