When dealing with dynamic library loading, A developer should:

* Implement robust input validation and sanitization techniques to prevent directory traversal and injection attacks.
* Only load libraries from trusted and verified sources, ensuring the integrity and authenticity of the libraries.
* Enforce strict access controls to prevent unauthorized library loading.
* Regularly update and patch libraries to address known vulnerabilities.
* Employ strong code signing and integrity verification mechanisms to ensure the integrity of dynamically loaded libraries.

Examples of secure implementations :

`Kotlin`:

```kotlin
fun validation(input : String){

    // Verify library file integrity
    val fileBytes = Files.readAllBytes(libraryFile.toPath())
    val digest = MessageDigest.getInstance("SHA-256")
    val fileDigest = digest.digest(fileBytes)
    val expectedChecksum = byteArrayOf(...)

    if (!fileDigest.contentEquals(expectedChecksum)) {
        return false
    }

    if (/* checks for .. paterns */ )
        return false  // Invalid path

    // Add additional validation checks specific to your implementation
    return true
}

fun loadDependency(unsanitized_user_input : String) {

    // validate your uses input
    if (!validation(unsanitized_user_input))
        throw IllegalArgumentException("Invalid input")

    // Load the library dynamically with the validated input
    System.load(unsanitized_user_input)

    // Perform some operation using the dynamically loaded library
    val result = libraryMethod()
}
```

`Dart`:

```dart
void validation(String input){

    // Verify library file integrity
    Uint8List fileBytes = libraryFile.readAsBytesSync();
    Digest fileDigest = SHA256Digest().process(fileBytes);
    Uint8List expectedChecksum = Uint8List.fromList([...]);

    if (fileDigest.bytes != expectedChecksum) {
        return false; // Invalid file checksum
    }

    if (/* checks for .. paterns */ )
        return false; // Invalid path
  
    // Add additional validation checks specific to your implementation
    return true;
}

void loadDependency(String unsanitized_user_input) {

    // sanitize user input
    if (validation(unsanitized_user_input) == false)
        throw FormatException("invalid input");

    // Dynamically load the library with a validated input
    final dylib = DynamicLibrary.open(unsanitized_user_input);

    // Resolve and call a function from the loaded library
    final libraryMethod = 
    dylib.lookupFunction<Pointer<Utf8> Function(), Pointer<Utf8> Function()>(
        'getSensitiveData');
    final result = libraryMethod();
}
```

`Swift`:

```swift
func validation(unsanitized_user_input: String){

    guard let fileData = fileManager.contents(atPath: libraryURL.path) else {
        return false // Failed to read file data
    }
    let fileDigest = SHA256.hash(data: fileData)

    // Compare the calculated checksum with the expected checksum
    let expectedChecksum: [UInt8] = [ /* Replace with your expected checksum */ ]
    if fileDigest != expectedChecksum {
        return false // Invalid file checksum

    if (/* checks for .. paterns */ )
        return false; // Invalid path
  
    // Add additional validation checks specific to your implementation
    return true;
  }
}

func loadDynamicLibrary(unsanitized_user_input: String) {

    // Validate your user input
    if !validation(unsanitized_user_input){
      throw CustomValidationError.invalidInput
    }

    // Attempt to dynamically load the library with validated user input 
    if let libraryHandle = dlopen(unsanitized_user_input, RTLD_NOW) {
        // Library loaded successfully, resolve a function that could contain malicous code
        if let method = dlsym(libraryHandle, "libraryMethod") {
            typealias FunctionType = @convention(c) () -> String
            let function = unsafeBitCast(libraryMethod, to: FunctionType.self)
            let result = function()
        }
        dlclose(libraryHandle)
    }
}
```
