--- pageClass: hidden-anchor-page --- # API Exception Handling > Exceptions are the main problems often encountered in the development process. Here are some common exceptions that may be encountered during the use of `YukiReflection` and how to deal with them. The exception description here will only synchronize the latest API version, and the exception of the older API version will not be described again, please always keep the API version up-to-date. ## Non-Blocking Exceptions > These exceptions will not cause the app to stop running (FC), but will print `E` level logs on the console, and may also stop continuing to execute related functions. ###### exception ::: danger loggerE Method/Constructor/Field match type "**TYPE**" not allowed ::: **Abnormal** A disallowed parameter type was set when looking up methods, constructors, and variables. > The following example ```kotlin // Find a method method { // Invalid type example is set param(false, 1, 0) // Invalid type example is set returnType = false } // Find a variable field { // Invalid type example is set type = false } ``` **Solution** In the search, `param`, `returnType`, `type` only accept `Class`, `String`, `VariousClass` types, and parameter instances cannot be passed in. > The following example ```kotlin // Find a method method { // ✅ Examples of correct usage param(BooleanType, IntType, IntType) // ✅ Examples of correct usage returnType = BooleanType // ✅ The following scheme is also correct returnType = "java.lang.Boolean" } // Find a variable field { // ✅ Examples of correct usage type = BooleanType } ``` ###### exception ::: danger loggerE NoSuchMethod/NoSuchConstructor/NoSuchField happend in \[**NAME**\] ::: **Abnormal** The target method, constructor, and variable were not found when looking for methods, constructors, and variables. **Solution** Please confirm that your search criteria can correctly match the specified methods, constructors and variables in the target `Class`. ###### exception ::: danger loggerE Trying **COUNT** times and all failure by RemedyPlan ::: **Abnormal** When using `RemedyPlan` to search for methods, constructors, and variables, the methods, constructors, and variables are still not found. **Solution** Please confirm the `RemedyPlan` parameter you set and the `Class` that exists in the current app, and try again. ###### exception ::: danger loggerE You must set a condition when finding a Method/Constructor/Field ::: **Abnormal** No conditions are set when looking for methods, constructors, and variables. > The following example ```kotlin method { // No conditions are set here } ``` **Solution** Please complete your search criteria and try again. ###### exception ::: danger loggerE Can't find this Class in \[**CLASSLOADER**\]: **CONTENT** Generated by YukiReflection#ReflectionTool ::: **Abnormal** The `Class` object to be searched for was not found via `ClassLoader.searchClass`. > The following example ```kotlin customClassLoader?.searchClass { from(...) // ... }.get() ``` **Solution** This is a security exception, please check the conditions you set, use the relevant tools to view the `Class` and bytecode object characteristics in the **Dex** and try again. ###### exception ::: danger loggerE Can't find this Method/Constructor/Field in \[**CLASS**\]: **CONTENT** Generated by YukiReflection#ReflectionTool ::: **Abnormal** The methods, constructors, and variables that need to be found cannot be found by specifying conditions. > The following example ```kotlin TargetClass.method { name = "test" param(BooleanType) } ``` **Solution** This is a security exception, please check the conditions you set, use the relevant tools to view the bytecode object characteristics in the `Class`, and try again. ###### exception ::: danger loggerE The number of VagueType must be at least less than the count of paramTypes ::: **Abnormal** Incorrect use of `VagueType` in `Method`, `Constructor` lookup conditions. > The following example ```kotlin TargetClass.method { name = "test" // param(VagueType) // param(VagueType, VagueType ...) } ``` **Solution** `VagueType` cannot be completely filled in method and constructor parameters. If there is such a requirement, please use `paramCount`. ###### exception ::: danger loggerE Field match type class is not found ::: **Abnormal** An instance of `Class` for `type` was not found in the lookup criteria set when looking up the variable. > The following example ```kotlin field { name = "test" // Assume that the Class of the type set here does not exist type = "com.example.TestClass" } ``` **Solution** Please check if `Class` of `type` in the lookup condition exists and try again. ###### exception ::: danger loggerE Method match returnType class is not found ::: **Abnormal** An instance of `Class` of `returnType` was not found in the search criteria set when looking up the method. > The following example ```kotlin method { name = "test" // Assume that the Class of returnType set here does not exist returnType = "com.example.TestClass" } ``` **Solution** Please check if `Class` of `returnType` in the lookup condition exists and try again. ###### exception ::: danger loggerE Method/Constructor match paramType\[**INDEX**\] class is not found ::: **Abnormal** The `Class` instance subscripted by the `index` number of `param` was not found in the search conditions set when searching for methods and constructors. ```kotlin method { name = "test" // Assume that the Class with subscript "No.1" set here does not exist param(StringClass, "com.example.TestClass", BooleanType) } ``` **Solution** Please check if the `Class` subscripted by the `index` number of `param` in the lookup condition exists and try again. ## Blocking Exceptions > These exceptions will directly cause the app to stop running (FC), at the same time print `E` level logs on the console. ###### exception ::: danger NoClassDefFoundError Can't find this Class in \[**CLASSLOADER**\]: **CONTENT** Generated by YukiReflection#ReflectionTool ::: **Abnormal** The `Class` object you were looking for was not found via `String.toClass(...)` or `classOf<...>()`. > The following example ```kotlin "com.demo.Test".toClass() ``` **Solution** Please check if the `Class` matched by the current string or entity exists in the current `ClassLoader` and try again. ###### exception ::: danger IllegalStateException ClassLoader \[**CLASSLOADER**\] is not a DexClassLoader ::: **Abnormal** Use `ClassLoader.searchClass` to find `Class` but currently `ClassLoader` does not extends `BaseDexClassLoader`. **Solution** This situation basically does not exist, unless the current app references a Non-ART platform executable (which not realistic) or the current `ClassLoader` is null. ###### exception ::: danger IllegalStateException VariousClass match failed of those **CLASSES** ::: **Abnormal** All `Class` were not found when creating indeterminate `Class` objects using `VariousClass`. **Solution** After checking whether there is a matching `Class` in the current app and try again. ###### exception ::: danger IllegalStateException paramTypes is empty, please use emptyParam() instead ::: **Abnormal** The empty `param` method is preserved when looking up methods, constructors. > The following example ```kotlin method { name = "test" // No parameters are filled in parentheses param() } ``` **Solution** To identify this method, the constructor has no parameters, you can have a setter method as follows. The first way, set `emptyParam` (recommended) > The following example ```kotlin method { name = "test" emptyParam() } ``` The second way, set `paramCount = 0` > The following example ```kotlin method { name = "test" paramCount = 0 } ``` ###### exception ::: danger IllegalStateException Cannot create classes cache for "android", please remove "name" param ::: **Abnormal** The `DexClassFinder` cache function `searchClass(name = ...)` is used in the System Framework ("android") app. > The following example ```kotlin searchClass(name = "test") { from(...) // ... }.get() ``` **Solution** Since the cache will store the found `Class` name in `SharedPreferences`, but the data directory does not exist in the System Framework, so please do not use this function in the System Framework. ###### exception ::: danger IllegalStateException Target Class type cannot cast to **TYPE** ::: **Abnormal** Wrong type declared when converting string class name to target `Class` using `Class.toClass`, `Class.toClassOrNull`, `GenericClass.argument` methods. The following uses the `Class.toClass` method as an example. > The following example ```kotlin // Assume the target type is Activity but it was wrongly cast to WrongClass type val clazz = "android.app.Activity".toClass() ``` **Solution** > The following example ```kotlin // Fill in the correct type val clazz1 = "android.app.Activity".toClass() // Do not fill in the generic declaration val clazz2 = "android.app.Activity".toClass() ``` Please ensure that the generic type declared after executing the method is the specified target `Class` type, and you do not need to fill in the generic declaration if the target type is not sure.