在運行工程時，突然出現此問題。首先，當然時一臉懵逼了。好在冷靜下來後，看日誌是jar包重複。關鍵是這個jar包我都沒有見過。
Duplicate class org.intellij.lang.annotations.Flow found in modules annotations-13.0.jar (org.jetbrains:annotations:13.0) and annotations-java5-15.0.jar (org.jetbrains:annotations-java5:15.0)
Duplicate class org.intellij.lang.annotations.Identifier found in modules annotations-13.0.jar (org.jetbrains:annotations:13.0) and annotations-java5-15.0.jar (org.jetbrains:annotations-java5:15.0)
Duplicate class org.intellij.lang.annotations.JdkConstants found in modules annotations-13.0.jar (org.jetbrains:annotations:13.0) and annotations-java5-15.0.jar (org.jetbrains:annotations-java5:15.0)
Duplicate class org.intellij.lang.annotations.JdkConstants$AdjustableOrientation found in modules annotations-13.0.jar (org.jetbrains:annotations:13.0) and annotations-java5-15.0.jar (org.jetbrains:annotations-java5:15.0)
Duplicate class org.intellij.lang.annotations.JdkConstants$BoxLayoutAxis found in modules annotations-13.0.jar (org.jetbrains:annotations:13.0) and annotations-java5-15.0.jar (org.jetbrains:annotations-java5:15.0)
Duplicate class org.intellij.lang.annotations.JdkConstants$CalendarMonth found in modules annotations-13.0.jar (org.jetbrains:annotations:13.0) and annotations-java5-15.0.jar (org.jetbrains:annotations-java5:15.0)
Duplicate class org.intellij.lang.annotations.JdkConstants$CursorType found in modules annotations-13.0.jar (org.jetbrains:annotations:13.0) and annotations-java5-15.0.jar (org.jetbrains:annotations-java5:15.0)
Duplicate class org.intellij.lang.annotations.JdkConstants$FlowLayoutAlignment found in modules annotations-13.0.jar (org.jetbrains:annotations:13.0) and annotations-java5-15.0.jar (org.jetbrains:annotations-java5:15.0)
Duplicate class org.intellij.lang.annotations.JdkConstants$FontStyle found in modules annotations-13.0.jar (org.jetbrains:annotations:13.0) and annotations-java5-15.0.jar (org.jetbrains:annotations-java5:15.0)
Duplicate class org.intellij.lang.annotations.JdkConstants$HorizontalAlignment found in modules annotations-13.0.jar (org.jetbrains:annotations:13.0) and annotations-java5-15.0.jar (org.jetbrains:annotations-java5:15.0)
Duplicate class org.intellij.lang.annotations.JdkConstants$InputEventMask found in modules annotations-13.0.jar (org.jetbrains:annotations:13.0) and annotations-java5-15.0.jar (org.jetbrains:annotations-java5:15.0)
Duplicate class org.intellij.lang.annotations.JdkConstants$ListSelectionMode found in modules annotations-13.0.jar (org.jetbrains:annotations:13.0) and annotations-java5-15.0.jar (org.jetbrains:annotations-java5:15.0)
Duplicate class org.intellij.lang.annotations.JdkConstants$PatternFlags found in modules annotations-13.0.jar (org.jetbrains:annotations:13.0) and annotations-java5-15.0.jar (org.jetbrains:annotations-java5:15.0)
Duplicate class org.intellij.lang.annotations.JdkConstants$TabLayoutPolicy found in modules annotations-13.0.jar (org.jetbrains:annotations:13.0) and annotations-java5-15.0.jar (org.jetbrains:annotations-java5:15.0)
Duplicate class org.intellij.lang.annotations.JdkConstants$TabPlacement found in modules annotations-13.0.jar (org.jetbrains:annotations:13.0) and annotations-java5-15.0.jar (org.jetbrains:annotations-java5:15.0)
Duplicate class org.intellij.lang.annotations.JdkConstants$TitledBorderJustification found in modules annotations-13.0.jar (org.jetbrains:annotations:13.0) and annotations-java5-15.0.jar (org.jetbrains:annotations-java5:15.0)
Duplicate class org.intellij.lang.annotations.JdkConstants$TitledBorderTitlePosition found in modules annotations-13.0.jar (org.jetbrains:annotations:13.0) and annotations-java5-15.0.jar (org.jetbrains:annotations-java5:15.0)
Duplicate class org.intellij.lang.annotations.JdkConstants$TreeSelectionMode found in modules annotations-13.0.jar (org.jetbrains:annotations:13.0) and annotations-java5-15.0.jar (org.jetbrains:annotations-java5:15.0)
Duplicate class org.intellij.lang.annotations.Language found in modules annotations-13.0.jar (org.jetbrains:annotations:13.0) and annotations-java5-15.0.jar (org.jetbrains:annotations-java5:15.0)
Duplicate class org.intellij.lang.annotations.MagicConstant found in modules annotations-13.0.jar (org.jetbrains:annotations:13.0) and annotations-java5-15.0.jar (org.jetbrains:annotations-java5:15.0)
Duplicate class org.intellij.lang.annotations.Pattern found in modules annotations-13.0.jar (org.jetbrains:annotations:13.0) and annotations-java5-15.0.jar (org.jetbrains:annotations-java5:15.0)
Duplicate class org.intellij.lang.annotations.PrintFormat found in modules annotations-13.0.jar (org.jetbrains:annotations:13.0) and annotations-java5-15.0.jar (org.jetbrains:annotations-java5:15.0)
Duplicate class org.intellij.lang.annotations.PrintFormatPattern found in modules annotations-13.0.jar (org.jetbrains:annotations:13.0) and annotations-java5-15.0.jar (org.jetbrains:annotations-java5:15.0)
Duplicate class org.intellij.lang.annotations.RegExp found in modules annotations-13.0.jar (org.jetbrains:annotations:13.0) and annotations-java5-15.0.jar (org.jetbrains:annotations-java5:15.0)
Duplicate class org.intellij.lang.annotations.Subst found in modules annotations-13.0.jar (org.jetbrains:annotations:13.0) and annotations-java5-15.0.jar (org.jetbrains:annotations-java5:15.0)
Duplicate class org.jetbrains.annotations.Contract found in modules annotations-13.0.jar (org.jetbrains:annotations:13.0) and annotations-java5-15.0.jar (org.jetbrains:annotations-java5:15.0)
Duplicate class org.jetbrains.annotations.Nls found in modules annotations-13.0.jar (org.jetbrains:annotations:13.0) and annotations-java5-15.0.jar (org.jetbrains:annotations-java5:15.0)
Duplicate class org.jetbrains.annotations.NonNls found in modules annotations-13.0.jar (org.jetbrains:annotations:13.0) and annotations-java5-15.0.jar (org.jetbrains:annotations-java5:15.0)
Duplicate class org.jetbrains.annotations.NotNull found in modules annotations-13.0.jar (org.jetbrains:annotations:13.0) and annotations-java5-15.0.jar (org.jetbrains:annotations-java5:15.0)
Duplicate class org.jetbrains.annotations.Nullable found in modules annotations-13.0.jar (org.jetbrains:annotations:13.0) and annotations-java5-15.0.jar (org.jetbrains:annotations-java5:15.0)
Duplicate class org.jetbrains.annotations.PropertyKey found in modules annotations-13.0.jar (org.jetbrains:annotations:13.0) and annotations-java5-15.0.jar (org.jetbrains:annotations-java5:15.0)
Duplicate class org.jetbrains.annotations.TestOnly found in modules annotations-13.0.jar (org.jetbrains:annotations:13.0) and annotations-java5-15.0.jar (org.jetbrains:annotations-java5:15.0)
Go to the documentation to learn how to Fix dependency resolution errors.
後來仔細看Gradle依賴，發現了這個依賴
implementation 'org.jetbrains:annotations-java5:15.0'
這個jar包有什麼作用呢。它是用於代碼檢查支持和代碼文檔。簡單來說，就是檢查我們的代碼的jar包。我將它替換成如下
implementation 'org.jetbrains:annotations:13.0'
萬事大吉了。衝突解決了。爲什麼替換成它呢。我是根據上面的報錯提示寫的。
Duplicate class org.intellij.lang.annotations.Flow found in modules annotations-13.0.jar (org.jetbrains:annotations:13.0) and annotations-java5-15.0.jar (org.jetbrains:annotations-java5:15.0)
這句話中括號裏面的就是我們所需要的依賴了。至於爲什麼，我想是因爲gradle版本問題吧。