Fix part of #5079 : Updated wiki for Gradle Build Failed - Task :util…

…ity:kaptGenerateStubsDebugKotlin FAILED (#5083)

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## Explanation

Fix part of #5079 : Updated wiki to add information about resolving
common setup error: Gradle Build Failed - Task
:utility:kaptGenerateStubsDebugKotlin FAILED

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## Essential Checklist
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- [x] The PR title and explanation each start with "Fix #bugnum: " (If
this PR fixes part of an issue, prefix the title with "Fix part of
#bugnum: ...".)
- [x] Any changes to
[scripts/assets](https://github.com/oppia/oppia-android/tree/develop/scripts/assets)
files have their rationale included in the PR explanation.
- [x] The PR follows the [style
guide](https://github.com/oppia/oppia-android/wiki/Coding-style-guide).
- [x] The PR does not contain any unnecessary code changes from Android
Studio
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## For UI-specific PRs only
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If your PR includes UI-related changes, then:
- Add screenshots for portrait/landscape for both a tablet & phone of
the before & after UI changes
- For the screenshots above, include both English and pseudo-localized
(RTL) screenshots (see [RTL
guide](https://github.com/oppia/oppia-android/wiki/RTL-Guidelines))
- Add a video showing the full UX flow with a screen reader enabled (see
[accessibility
guide](https://github.com/oppia/oppia-android/wiki/Accessibility-A11y-Guide))
- Add a screenshot demonstrating that you ran affected Espresso tests
locally & that they're passing

wiki/Troubleshooting-Installation.md

@@ -39,6 +39,23 @@ Here are some general troubleshooting tips for oppia-android. The specific platf
    or `Module not specified` while running Unit Tests, try to downgrade Android Studio to [Bumblebee (Patch 3)](https://developer.android.com/studio/archive). That should resolve this issue.
 
 
+7. If you encounter this error while building gradle:
+
+   ```
+   > Task :utility:kaptGenerateStubsDebugKotlin FAILED
+   Execution failed for task ':utility:kaptGenerateStubsDebugKotlin'.
+   > Could not resolve all files for configuration ':utility:debugCompileClasspath'.
+      > Failed to transform model.jar (project :model) to match attributes {artifactType=android-classes, org.gradle.category=library, org.gradle.dependency.bundling=external, org.gradle.jvm.version=15, org.gradle.libraryelements=jar, org.gradle.usage=java-api}.
+         > Execution failed for JetifyTransform: E:\Android\open-source\oppia-android\model\build\libs\model.jar.
+            > Failed to transform 'E:\Android\open-source\oppia-android\model\build\libs\model.jar' using Jetifier. Reason: Unsupported class file major version 59. (Run with --stacktrace for more details.)
+   ```
+   You are seeing this because Oppia android currently compiles with Java 8, or 9. Higher versions of Java are not supported by our version of Gradle.
+
+   The `model.jar` was compiled with Java 15/major version 59, hence the incompatibility.
+
+
+   To fix this error, you need to lower the version of Java to compile the JAR file. Please see [here](https://developer.android.com/studio/intro/studio-config#jdk) for more information about Java versions.
+
 ### Bazel issues
 
 1. No matching toolchains (sdk_toolchain_type)