# javax.security.auth.callback

***

**1. Password Callback Handler**

```java
import javax.security.auth.callback.*;

public class PasswordCallbackHandler implements CallbackHandler {

    private String password;

    public PasswordCallbackHandler(String password) {
        this.password = password;
    }

    @Override
    public void handle(Callback[] callbacks) throws UnsupportedCallbackException {
        for (Callback callback : callbacks) {
            if (callback instanceof PasswordCallback) {
                PasswordCallback pCallback = (PasswordCallback) callback;
                pCallback.setPassword(password.toCharArray());
            }
        }
    }
}
```

**2. Username and Password Callback Handler**

```java
import javax.security.auth.callback.*;

public class UsernamePasswordCallbackHandler implements CallbackHandler {

    private String username;
    private String password;

    public UsernamePasswordCallbackHandler(String username, String password) {
        this.username = username;
        this.password = password;
    }

    @Override
    public void handle(Callback[] callbacks) throws UnsupportedCallbackException {
        for (Callback callback : callbacks) {
            if (callback instanceof NameCallback) {
                NameCallback nCallback = (NameCallback) callback;
                nCallback.setName(username);
            } else if (callback instanceof PasswordCallback) {
                PasswordCallback pCallback = (PasswordCallback) callback;
                pCallback.setPassword(password.toCharArray());
            }
        }
    }
}
```

**3. Choice Callback Handler**

```java
import javax.security.auth.callback.*;

public class ChoiceCallbackHandler implements CallbackHandler {

    private String choice;

    public ChoiceCallbackHandler(String choice) {
        this.choice = choice;
    }

    @Override
    public void handle(Callback[] callbacks) throws UnsupportedCallbackException {
        for (Callback callback : callbacks) {
            if (callback instanceof ChoiceCallback) {
                ChoiceCallback cCallback = (ChoiceCallback) callback;
                cCallback.setSelectedIndex(Integer.parseInt(choice));
            }
        }
    }
}
```

**4. Text Input Callback Handler**

```java
import javax.security.auth.callback.*;

public class TextInputCallbackHandler implements CallbackHandler {

    private String text;

    public TextInputCallbackHandler(String text) {
        this.text = text;
    }

    @Override
    public void handle(Callback[] callbacks) throws UnsupportedCallbackException {
        for (Callback callback : callbacks) {
            if (callback instanceof TextInputCallback) {
                TextInputCallback tCallback = (TextInputCallback) callback;
                tCallback.setText(text);
            }
        }
    }
}
```

**5. Confirmation Callback Handler**

```java
import javax.security.auth.callback.*;

public class ConfirmationCallbackHandler implements CallbackHandler {

    private boolean confirmed;

    public ConfirmationCallbackHandler(boolean confirmed) {
        this.confirmed = confirmed;
    }

    @Override
    public void handle(Callback[] callbacks) throws UnsupportedCallbackException {
        for (Callback callback : callbacks) {
            if (callback instanceof ConfirmationCallback) {
                ConfirmationCallback cCallback = (ConfirmationCallback) callback;
                cCallback.setConfirmed(confirmed);
            }
        }
    }
}
```

**6. Mapping Callback Handler**

```java
import javax.security.auth.callback.*;

public class MappingCallbackHandler implements CallbackHandler {

    private Map<String, String> mappings;

    public MappingCallbackHandler(Map<String, String> mappings) {
        this.mappings = mappings;
    }

    @Override
    public void handle(Callback[] callbacks) throws UnsupportedCallbackException {
        for (Callback callback : callbacks) {
            if (callback instanceof MappingCallback) {
                MappingCallback mCallback = (MappingCallback) callback;
                String value = mappings.get(mCallback.getPrompt());
                mCallback.setValue(value);
            }
        }
    }
}
```

**7. Secure Input Callback Handler**

```java
import javax.security.auth.callback.*;

public class SecureInputCallbackHandler implements CallbackHandler {

    private SecureInputStream inputStream;

    public SecureInputCallbackHandler(SecureInputStream inputStream) {
        this.inputStream = inputStream;
    }

    @Override
    public void handle(Callback[] callbacks) throws UnsupportedCallbackException {
        for (Callback callback : callbacks) {
            if (callback instanceof SecureInputCallback) {
                SecureInputCallback sCallback = (SecureInputCallback) callback;
                byte[] data = new byte[sCallback.getSize()];
                inputStream.read(data);
                sCallback.setData(data);
            }
        }
    }
}
```

**8. Secure Output Callback Handler**

```java
import javax.security.auth.callback.*;

public class SecureOutputCallbackHandler implements CallbackHandler {

    private SecureOutputStream outputStream;

    public SecureOutputCallbackHandler(SecureOutputStream outputStream) {
        this.outputStream = outputStream;
    }

    @Override
    public void handle(Callback[] callbacks) throws UnsupportedCallbackException {
        for (Callback callback : callbacks) {
            if (callback instanceof SecureOutputCallback) {
                SecureOutputCallback sCallback = (SecureOutputCallback) callback;
                outputStream.write(sCallback.getData());
            }
        }
    }
}
```

**9. PBE Key Derivation Callback Handler**

```java
import javax.security.auth.callback.*;

public class PBEKeyDerivationCallbackHandler implements CallbackHandler {

    private String password;

    public PBEKeyDerivationCallbackHandler(String password) {
        this.password = password;
    }

    @Override
    public void handle(Callback[] callbacks) throws UnsupportedCallbackException {
        for (Callback callback : callbacks) {
            if (callback instanceof PBEKeyDerivationCallback) {
                PBEKeyDerivationCallback kCallback = (PBEKeyDerivationCallback) callback;
                kCallback.setPassword(password.toCharArray());
            }
        }
    }
}
```

**10. Refreshing Callback Handler**

```java
import javax.security.auth.callback.*;

public class RefreshingCallbackHandler implements CallbackHandler {

    private CallbackHandler underlyingHandler;

    public RefreshingCallbackHandler(CallbackHandler underlyingHandler) {
        this.underlyingHandler = underlyingHandler;
    }

    @Override
    public void handle(Callback[] callbacks) throws UnsupportedCallbackException {
        // Perform any necessary pre-processing or refreshing of underlying handler before passing callbacks
        underlyingHandler.handle(callbacks);
    }
}
```

**11. Composite Callback Handler**

```java
import javax.security.auth.callback.*;

public class CompositeCallbackHandler implements CallbackHandler {

    private List<CallbackHandler> handlers;

    public CompositeCallbackHandler(List<CallbackHandler> handlers) {
        this.handlers = handlers;
    }

    @Override
    public void handle(Callback[] callbacks) throws UnsupportedCallbackException {
        for (CallbackHandler handler : handlers) {
            handler.handle(callbacks);
        }
    }
}
```

**12. Caching Callback Handler**

```java
import javax.security.auth.callback.*;

public class CachingCallbackHandler implements CallbackHandler {

    private Map<Class<? extends Callback>, Callback> cache;

    public CachingCallbackHandler() {
        cache = new HashMap<>();
    }

    @Override
    public void handle(Callback[] callbacks) throws UnsupportedCallbackException {
        for (Callback callback : callbacks) {
            Callback cached = cache.get(callback.getClass());
            if (cached != null) {
                callback.copyFrom(cached);
                continue;
            }
            // Perform actual callback handling
            UnderlyingCallbackHandler.handle(callbacks);
            // Cache the result
            cache.put(callback.getClass(), callback);
        }
    }
}
```

**13. Anonymous Callback Handler**

```java
import javax.security.auth.callback.*;

public class AnonymousCallbackHandler implements CallbackHandler {

    @Override
    public void handle(Callback[] callbacks) throws UnsupportedCallbackException {
        // Empty implementation, as no callbacks are expected or needed
    }
}
```

**14. Password Callback Handler with Regex Validation**

```java
import java.util.regex.*;
import javax.security.auth.callback.*;

public class PasswordCallbackHandlerWithRegexValidation implements CallbackHandler {

    private Pattern passwordPattern;

    public PasswordCallbackHandlerWithRegexValidation(String passwordPattern) {
        this.passwordPattern = Pattern.compile(passwordPattern);
    }

    @Override
    public void handle(Callback[] callbacks) throws UnsupportedCallbackException, PasswordCreationException {
        for (Callback callback : callbacks) {
            if (callback instanceof PasswordCallback) {
                PasswordCallback pCallback = (PasswordCallback) callback;
                char[] password = pCallback.getPassword();
                if (!passwordPattern.matcher(new String(password)).matches()) {
                    throw new PasswordCreationException("Password does not meet complexity requirements");
                }
            }
        }
    }
}
```

**15. Username and Password Callback Handler with Database Lookup**

```java
import java.sql.*;
import javax.security.auth.callback.*;

public class UsernamePasswordCallbackHandlerWithDatabaseLookup implements CallbackHandler {

    private Connection connection;

    public UsernamePasswordCallbackHandlerWithDatabaseLookup(Connection connection) {
        this.connection = connection;
    }

    @Override
    public void handle(Callback[] callbacks) throws UnsupportedCallbackException {
        for (Callback callback : callbacks) {
            if (callback instanceof NameCallback) {
                NameCallback nCallback = (NameCallback) callback;
                nCallback.setName(retrieveUsernameFromDatabase(nCallback.getPrompt()));
            } else if (callback instanceof PasswordCallback) {
                PasswordCallback pCallback = (PasswordCallback) callback;
                pCallback.setPassword(retrievePasswordFromDatabase(nCallback.getName()).toCharArray());
            }
        }
    }

    private String retrieveUsernameFromDatabase(String prompt) throws SQLException {
        // Implement logic to retrieve username from database using the prompt as a search parameter
    }

    private String retrievePasswordFromDatabase(String username) throws SQLException {
        // Implement logic to retrieve password from database using the username as a search parameter
    }
}
```

**16. Choice Callback Handler with Custom Choices**

```java
import javax.security.auth.callback.*;

public class ChoiceCallbackHandlerWithCustomChoices implements CallbackHandler {

    private Map<String, Integer> choices;

    public ChoiceCallbackHandlerWithCustomChoices(Map<String, Integer> choices) {
        this.choices = choices;
    }

    @Override
    public void handle(Callback[] callbacks) throws UnsupportedCallbackException {
        for (Callback callback : callbacks) {
            if (callback instanceof ChoiceCallback) {
                ChoiceCallback cCallback = (ChoiceCallback) callback;
                cCallback.setDefaultChoice(choices.get(cCallback.getPrompt()));
                cCallback.setChoices(choices.keySet().toArray(new String[0]));
            }
        }
    }
}
```

**17. Text Input Callback Handler with Input Validation**

```java
import java.util.regex.*;
import javax.security.auth.callback.*;

public class TextInputCallbackHandlerWithInputValidation implements CallbackHandler {

    private Pattern inputPattern;

    public TextInputCallbackHandlerWithInputValidation(String inputPattern) {
        this.inputPattern = Pattern.compile(inputPattern);
    }

    @Override
    public void handle(Callback[] callbacks) throws UnsupportedCallbackException, PasswordCreationException {
        for (Callback callback : callbacks) {
            if (callback instanceof TextInputCallback) {
                TextInputCallback tCallback = (TextInputCallback) callback;
                String input = tCallback.getText();
                if (!inputPattern.matcher(input).matches()) {
                    throw new PasswordCreationException("Input does not meet validation requirements");
                }
            }
        }
    }
}
```

**18. Confirmation Callback Handler with Custom Message**

```java
import javax.security.auth.callback.*;

public class ConfirmationCallbackHandlerWithCustomMessage implements CallbackHandler {

    private String message;

    public ConfirmationCallbackHandlerWithCustomMessage(String message) {
        this.message = message;
    }

    @Override
    public void handle(Callback[] callbacks) throws UnsupportedCallbackException {
        for (Callback callback : callbacks) {
            if (callback instanceof ConfirmationCallback) {
                ConfirmationCallback cCallback = (ConfirmationCallback) callback;
                cCallback.setMessage(message);
            }
        }
    }
}
```

**19. Mapping Callback Handler with Fallback**

```java
import javax.security.auth.callback.*;

public class MappingCallbackHandlerWithFallback implements CallbackHandler {

    private Map<String, String> primaryMappings;
    private Map<String, String> fallbackMappings;

    public MappingCallbackHandlerWithFallback(Map<String, String> primaryMappings, Map<String, String> fallbackMappings) {
        this.primaryMappings = primaryMappings;
        this.fallbackMappings = fallbackMappings;
    }

    @Override
    public void handle(Callback[] callbacks) throws UnsupportedCallbackException {
        for (Callback callback : callbacks) {
            if (callback instanceof MappingCallback) {
                MappingCallback mCallback = (MappingCallback) callback;
                String value = primaryMappings.get(mCallback.getPrompt());
                if (value == null) {
                    value = fallbackMappings.get(mCallback.getPrompt());
                }
                mCallback.setValue(value);
            }
        }
    }
}
```

**20. Secure Input Callback Handler with Encryption**

```java
import javax.crypto.*;
import javax.security.auth.callback.*;

public class SecureInputCallbackHandlerWithEncryption implements CallbackHandler {

    private Cipher encryptor;

    public SecureInputCallbackHandlerWithEncryption(Cipher encryptor) {
        this.encryptor = encryptor;
    }

    @Override
    public void handle(Callback[] callbacks) throws UnsupportedCallbackException {
        for (Callback callback : callbacks) {
            if (callback instanceof SecureInputCallback) {
                SecureInputCallback sCallback = (SecureInputCallback) callback;
                byte[] data = new byte[sCallback.getSize()];
                encryptor.update(data, 0, data.length);
                sCallback.setData(data);
            }
        }
    }
}
```

**21. Secure Output Callback Handler with Decryption**

```java
import javax.crypto.*;
import javax.security.auth.callback.*;

public class SecureOutputCallbackHandlerWithDecryption implements CallbackHandler {

    private Cipher decryptor;

    public SecureOutputCallbackHandlerWithDecryption(Cipher decryptor) {
        this.decryptor = decryptor;
    }

    @Override
    public void handle(Callback[] callbacks) throws UnsupportedCallbackException {
        for (Callback callback : callbacks) {
            if (callback instanceof SecureOutputCallback) {
                SecureOutputCallback sCallback = (SecureOutputCallback) callback;
                byte[] data = sCallback.getData();
                decryptor.update(data, 0, data.length);
                sCallback.setData(data);
            }
        }
    }
}
```

**22. PBE Key Derivation Callback Handler with Salt**

```java
import javax.crypto.spec.*;
import javax.security.auth.callback.*;

public class PBEKeyDerivationCallbackHandlerWithSalt implements CallbackHandler {

    private PBEKeySpec pbeKeySpec;

    public PBEKeyDerivationCallbackHandlerWithSalt(String password, byte[] salt) {
        pbeKeySpec = new PBEKeySpec(password.toCharArray(), salt, 1024, 256);
    }

    @Override
    public void handle(Callback[] callbacks) throws UnsupportedCallbackException {
        for (Callback callback : callbacks) {
            if (callback instanceof PBEKeyDerivationCallback) {
                PBEKeyDerivationCallback kCallback = (PBEKeyDerivationCallback) callback;
                kCallback.setPBEKeySpec(pbeKeySpec);
            }
        }
    }
}
```

**23. Refreshing Callback Handler with Cache Expiration**

```java
import javax.security.auth.callback.*;

public class RefreshingCallbackHandlerWithCacheExpiration implements CallbackHandler {

    private CallbackHandler underlyingHandler;
    private long expirationTime;

    public RefreshingCallbackHandlerWithCacheExpiration(CallbackHandler underlyingHandler, long expirationTime) {
        this.underlyingHandler = underlyingHandler;
        this.expirationTime = expirationTime;
    }

    @Override
    public void handle(Callback[] callbacks) throws UnsupportedCallbackException {
        // Check if cache has expired
        if (System.currentTimeMillis() > expirationTime) {
            // Refresh cache by calling underlying handler
            underlyingHandler.handle(callbacks);
            // Reset expiration time
            expirationTime = System.currentTimeMillis() + expirationTime;
        }
        // Pass callbacks to underlying handler
        underlyingHandler.handle(callbacks);
    }
}
```

**24. Composite Callback Handler with Priority**

```java
import javax.security.auth.callback.*;

public class CompositeCallbackHandlerWithPriority implements CallbackHandler {

    private List<CallbackHandler> handlers;
    private Map<Class<? extends Callback>, Integer> priorities;

    public CompositeCallbackHandlerWithPriority(List<CallbackHandler> handlers, Map<Class<? extends Callback>, Integer> priorities) {
        this.handlers = handlers;
        this.priorities = priorities;
    }

    @Override
    public void handle(Callback[] callbacks) throws UnsupportedCallbackException {
        // Sort callbacks by priority
        Arrays.sort(callbacks, (c1, c2) -> priorities.get(c1.getClass()) - priorities.get(c2.getClass()));
        // Pass sorted callbacks to handlers in order of priority
        for (CallbackHandler handler : handlers) {
            handler.handle(callbacks);
        }
    }
}
```

**25. Caching Callback Handler with Pre-Caching**

```java
import javax.security.auth.callback.*;

public class CachingCallbackHandlerWithPreCaching implements CallbackHandler {

    private Map<Class<? extends Callback>, Callback> cache;
    private List<Callback> preCachedCallbacks;

    public CachingCallbackHandlerWithPreCaching(List<Callback> preCachedCallbacks) {
        cache = new HashMap<>();
        this.preCachedCallbacks = preCachedCallbacks;
    }

    @Override
    public void handle(Callback[] callbacks) throws UnsupportedCallbackException {
        // Cache pre-cached callbacks
        for (Callback callback : preCachedCallbacks) {
            cache.put(callback.getClass(), callback);
        }
        // Pass callbacks to underlying handler and cache results
        UnderlyingCallbackHandler.handle(callbacks);
        for (Callback callback : callbacks) {
            cache.put(callback.getClass(), callback);
        }
    }
}
```

**26. Password Callback Handler with Key Derivation**

```java
import javax.crypto.*;
import javax.security.auth.callback.*;

public class PasswordCallbackHandlerWithKeyDerivation implements CallbackHandler {

    private SecretKeyFactory keyFactory;
    private String algorithm;

    public PasswordCallbackHandlerWithKeyDerivation(String algorithm) throws NoSuchAlgorithmException {
        keyFactory = SecretKeyFactory.getInstance(algorithm);
        this.algorithm = algorithm;
    }

    @Override
    public void handle(Callback[] callbacks) throws UnsupportedCallbackException {
        for (Callback callback : callbacks) {
            if (callback instanceof PasswordCallback) {
                PasswordCallback pCallback = (PasswordCallback) callback;
                SecretKey key = keyFactory.generateSecret(new PBEKeySpec(pCallback.getPassword(), "salt".getBytes(), 1024, 256));
                pCallback.setPassword(null);
                pCallback.setKey(key.getEncoded());
            }
        }
    }
}
```

**27. Username and Password Callback Handler with Encryption**

```java
import javax.crypto.*;
import javax.security.auth.callback.*;

public class UsernamePasswordCallbackHandlerWithEncryption implements CallbackHandler {

    private Cipher encryptor;

    public UsernamePasswordCallbackHandlerWithEncryption(Cipher encryptor) {
        this.encryptor = encryptor;
    }

    @Override
    public void handle(Callback[] callbacks) throws UnsupportedCallbackException {
        for (Callback callback : callbacks) {
            if (callback instanceof NameCallback) {
                NameCallback nCallback = (NameCallback) callback;
                nCallback.setName(encryptor.doFinal(nCallback.getName().getBytes()));

```