Utility Classes

/**
 * Contains configuration information used to build client libraries.
 */
class Configuration {
    /**
     * Gets the global configuration instance.
     * @return Global Configuration instance
     */
    public static Configuration getGlobalConfiguration();
    
    /**
     * Creates a new Configuration instance.
     */
    public Configuration();
    
    /**
     * Creates a Configuration instance with the provided configuration source.
     * @param configurationSource Source of configuration values
     */
    public Configuration(ConfigurationSource configurationSource);
    
    /**
     * Gets the value of the configuration.
     * @param name Name of the configuration property
     * @return Configuration value or null if not found
     */
    public String get(String name);
    
    /**
     * Gets the value of the configuration.
     * @param name Name of the configuration property
     * @param defaultValue Default value if configuration is not found
     * @return Configuration value or default value
     */
    public String get(String name, String defaultValue);
    
    /**
     * Gets the value of the configuration and converts it to the specified type.
     * @param <T> Type to convert to
     * @param name Name of the configuration property
     * @param converter Function to convert string to desired type
     * @return Converted configuration value or null
     */
    public <T> T get(String name, Function<String, T> converter);
    
    /**
     * Gets the value of the configuration and converts it to the specified type.
     * @param <T> Type to convert to  
     * @param name Name of the configuration property
     * @param converter Function to convert string to desired type
     * @param defaultValue Default value if configuration is not found
     * @return Converted configuration value or default value
     */
    public <T> T get(String name, Function<String, T> converter, T defaultValue);
    
    /**
     * Gets the value of the configuration with generic default value.
     * @param <T> Type of the configuration value
     * @param name Name of the configuration property
     * @param defaultValue Default value if configuration is not found
     * @return Configuration value or default value
     */
    public <T> T get(String name, T defaultValue);
    
    /**
     * Gets the value of the configuration property.
     * @param <T> Type of the configuration property
     * @param property The configuration property
     * @return Configuration value or null if not found
     */
    public <T> T get(ConfigurationProperty<T> property);
    
    /**
     * Determines if the configuration contains the specified property.
     * @param property The configuration property to check
     * @return true if the configuration contains the property
     */
    public boolean contains(ConfigurationProperty<?> property);
    
    /**
     * Adds a configuration property.
     * @param name Name of the configuration property
     * @param value Value of the configuration property
     * @return Updated Configuration instance
     */
    public Configuration put(String name, String value);
    
    /**
     * Removes a configuration property.
     * @param name Name of the configuration property to remove
     * @return Updated Configuration instance
     */
    public Configuration remove(String name);
    
    /**
     * Determines if the configuration contains the specified property.
     * @param name Name of the configuration property
     * @return true if the configuration contains the property
     */
    public boolean contains(String name);
    
    /**
     * Creates a clone of the Configuration object.
     * @return Cloned Configuration instance
     */
    public Configuration clone();
}

/**
 * Represents configuration property with type safety and validation.
 */
class ConfigurationProperty<T> {
    /**
     * Gets the property name.
     * @return Property name
     */
    public String getName();
    
    /**
     * Gets the default value for the property.
     * @return Default value
     */
    public T getDefaultValue();
    
    /**
     * Converts string value to property type.
     * @param value String value to convert
     * @return Converted value
     */
    public T convert(String value);
}

/**
 * Builder for Configuration instances.
 */
class ConfigurationBuilder {
    /**
     * Creates a ConfigurationBuilder.
     */
    public ConfigurationBuilder();
    
    /**
     * Adds a configuration source.
     * @param configurationSource Source to add
     * @return Updated ConfigurationBuilder
     */
    public ConfigurationBuilder putConfigurationSource(ConfigurationSource configurationSource);
    
    /**
     * Builds the Configuration instance.
     * @return Configuration instance
     */
    public Configuration build();
}

/**
 * Interface for configuration sources.
 */
interface ConfigurationSource {
    /**
     * Gets properties from the configuration source.
     * @param name Property name
     * @return Property value or null if not found
     */
    String getPropertyValue(String name);
}

/**
 * Context offers a means of passing arbitrary data (key-value pairs) to pipeline policies.
 */
class Context {
    /**
     * Signifies that no data needs to be passed to the pipeline.
     */
    public static final Context NONE;
    
    /**
     * Constructs a new Context object with the specified key-value pair.
     * @param key The key with which the specified value should be associated
     * @param value The value to be associated with the specified key
     * @throws IllegalArgumentException If key is null
     */
    public Context(Object key, Object value);
    
    /**
     * Adds a new immutable Context object with the specified key-value pair to the existing Context chain.
     * @param key The key with which the specified value is to be associated
     * @param value The value to be associated with the specified key
     * @return Context object containing the specified pair added to the set of pairs
     * @throws IllegalArgumentException If key is null
     */
    public Context addData(Object key, Object value);
    
    /**
     * Gets the value associated with the specified key.
     * @param key The key whose associated value is to be returned
     * @return Optional containing the value associated with the key, empty Optional otherwise
     * @throws IllegalArgumentException If key is null
     */
    public Optional<Object> getData(Object key);
    
    /**
     * Gets all values as a Map.
     * @return Map containing all key-value pairs in the context
     */
    public Map<Object, Object> getValues();
}

/**
 * This class is a logging abstraction layer over SLF4J.
 */
class ClientLogger {
    /**
     * Creates a ClientLogger for the specified class.
     * @param clazz Class to create logger for
     */
    public ClientLogger(Class<?> clazz);
    
    /**
     * Creates a ClientLogger with the specified name.
     * @param className Name for the logger
     */
    public ClientLogger(String className);
    
    /**
     * Logs a message at verbose level.
     * @param message Message to log
     */
    public void verbose(String message);
    
    /**
     * Logs a message with arguments at verbose level.
     * @param format Message format string
     * @param args Arguments for the format string
     */
    public void verbose(String format, Object... args);
    
    /**
     * Logs an informational message.
     * @param message Message to log
     */
    public void info(String message);
    
    /**
     * Logs an informational message with arguments.
     * @param format Message format string
     * @param args Arguments for the format string
     */
    public void info(String format, Object... args);
    
    /**
     * Logs a warning message.
     * @param message Message to log
     */
    public void warning(String message);
    
    /**
     * Logs a warning message with arguments.
     * @param format Message format string
     * @param args Arguments for the format string
     */
    public void warning(String format, Object... args);
    
    /**
     * Logs an error message.
     * @param message Message to log
     */
    public void error(String message);
    
    /**
     * Logs an error message with throwable.
     * @param message Message to log
     * @param throwable Exception to log
     */
    public void error(String message, Throwable throwable);
    
    /**
     * Logs an error message with arguments.
     * @param format Message format string
     * @param args Arguments for the format string
     */
    public void error(String format, Object... args);
    
    /**
     * Determines if logging is enabled for the specified log level.
     * @param logLevel Log level to check
     * @return true if logging is enabled for the level
     */
    public boolean canLogAtLevel(LogLevel logLevel);
    
    /**
     * Logs a message at the specified level.
     * @param logLevel Level to log at
     * @param message Message to log
     */
    public void log(LogLevel logLevel, String message);
    
    /**
     * Logs a message with arguments at the specified level.
     * @param logLevel Level to log at
     * @param format Message format string
     * @param args Arguments for the format string
     */
    public void log(LogLevel logLevel, String format, Object... args);
    
    /**
     * Logs a message with throwable at the specified level.
     * @param logLevel Level to log at
     * @param message Message to log
     * @param throwable Exception to log
     */
    public void log(LogLevel logLevel, String message, Throwable throwable);
}

/**
 * Enumeration of log levels.
 */
enum LogLevel {
    /**
     * Indicates that log level is not set.
     */
    NOT_SET(0),
    
    /**
     * Verbose logging level.
     */
    VERBOSE(1),
    
    /**
     * Informational logging level.
     */
    INFORMATIONAL(2),
    
    /**
     * Warning logging level.
     */
    WARNING(3),
    
    /**
     * Error logging level.
     */
    ERROR(4);
    
    private final int value;
    
    LogLevel(int value) {
        this.value = value;
    }
    
    /**
     * Gets the numeric value of the log level.
     * @return Numeric value
     */
    public int getValue() {
        return value;
    }
    
    /**
     * Creates LogLevel from numeric value.
     * @param value Numeric value
     * @return Corresponding LogLevel
     */
    public static LogLevel fromValue(int value);
}

/**
 * Synchronous poller for long-running operations.
 */
class SyncPoller<T, U> {
    /**
     * Polls and returns the current status of the long-running operation.
     * @return PollResponse representing the current status
     */
    public PollResponse<T> poll();
    
    /**
     * Waits for polling to complete.
     * @return Final PollResponse when operation completes
     */
    public PollResponse<T> waitForCompletion();
    
    /**
     * Waits for polling to complete within the specified timeout.
     * @param timeout Maximum time to wait
     * @return Final PollResponse when operation completes
     */
    public PollResponse<T> waitForCompletion(Duration timeout);
    
    /**
     * Waits until the long-running operation reaches a specified status.
     * @param statusToWaitFor Status to wait for
     * @return PollResponse when the specified status is reached
     */
    public PollResponse<T> waitUntil(LongRunningOperationStatus statusToWaitFor);
    
    /**
     * Waits until the long-running operation reaches a specified status within timeout.
     * @param statusToWaitFor Status to wait for
     * @param timeout Maximum time to wait
     * @return PollResponse when the specified status is reached
     */
    public PollResponse<T> waitUntil(LongRunningOperationStatus statusToWaitFor, Duration timeout);
    
    /**
     * Gets the final result of the long-running operation.
     * @return Final result when operation completes
     */
    public U getFinalResult();
    
    /**
     * Cancels the long-running operation.
     */
    public void cancelOperation();
    
    /**
     * Gets the polling interval.
     * @return Duration between polls
     */
    public Duration getPollInterval();
}

/**
 * Asynchronous poller for long-running operations.
 */
class PollerFlux<T, U> {
    /**
     * Creates a PollerFlux instance.
     * @param pollInterval Duration between polling attempts
     * @param pollOperation Function that performs polling
     * @param cancelOperation Function that cancels the operation
     * @param fetchResultOperation Function that fetches the final result
     * @return PollerFlux instance
     */
    public static <T, U> PollerFlux<T, U> create(
        Duration pollInterval,
        Function<PollingContext<T>, Mono<PollResponse<T>>> pollOperation,
        Function<PollingContext<T>, Mono<T>> cancelOperation,
        Function<PollingContext<T>, Mono<U>> fetchResultOperation);
    
    /**
     * Subscribes to the polling flux.
     * @return Flux of PollResponse objects
     */
    public Flux<PollResponse<T>> flux();
    
    /**
     * Gets the final result when polling completes.
     * @return Mono containing the final result
     */
    public Mono<U> getFinalResult();
    
    /**
     * Cancels the long-running operation.
     * @return Mono representing the cancellation operation
     */
    public Mono<T> cancelOperation();
    
    /**
     * Gets the last polling response.
     * @return Mono containing the last poll response
     */
    public Mono<PollResponse<T>> getLastPollResponse();
    
    /**
     * Creates a SyncPoller from this PollerFlux.
     * @return SyncPoller instance
     */
    public SyncPoller<T, U> getSyncPoller();
}

/**
 * Response from a polling operation.
 */
class PollResponse<T> {
    /**
     * Creates a PollResponse.
     * @param status Status of the long-running operation
     * @param value Current value from the service
     */
    public PollResponse(LongRunningOperationStatus status, T value);
    
    /**
     * Creates a PollResponse.
     * @param status Status of the long-running operation
     * @param value Current value from the service
     * @param retryAfter Suggested retry interval
     */
    public PollResponse(LongRunningOperationStatus status, T value, Duration retryAfter);
    
    /**
     * Gets the status of the long-running operation.
     * @return Operation status
     */
    public LongRunningOperationStatus getStatus();
    
    /**
     * Gets the current value from the service.
     * @return Current poll value
     */
    public T getValue();
    
    /**
     * Gets the suggested retry interval.
     * @return Retry interval or null if not specified
     */
    public Duration getRetryAfter();
}

/**
 * Represents the status of a long-running operation.
 */
enum LongRunningOperationStatus {
    /**
     * The operation is not started.
     */
    NOT_STARTED,
    
    /**
     * The operation is in progress.
     */
    IN_PROGRESS,
    
    /**
     * The operation completed successfully.
     */
    SUCCESSFULLY_COMPLETED,
    
    /**
     * The operation failed.
     */
    FAILED,
    
    /**
     * The operation was cancelled.
     */
    USER_CANCELLED;
    
    /**
     * Checks if the status represents a completed operation.
     * @return true if operation is complete
     */
    public boolean isComplete() {
        return this == SUCCESSFULLY_COMPLETED || this == FAILED || this == USER_CANCELLED;
    }
}

/**
 * Context passed to polling operations.
 */
class PollingContext<T> {
    /**
     * Gets the latest poll response.
     * @return Latest PollResponse
     */
    public PollResponse<T> getLatestResponse();
    
    /**
     * Sets data in the polling context.
     * @param key Data key
     * @param value Data value
     */
    public void setData(String key, Object value);
    
    /**
     * Gets data from the polling context.
     * @param key Data key
     * @return Data value or null if not found
     */
    public Object getData(String key);
    
    /**
     * Gets the HTTP pipeline for making requests.
     * @return HttpPipeline instance
     */
    public HttpPipeline getHttpPipeline();
    
    /**
     * Gets the serializer adapter.
     * @return SerializerAdapter instance
     */
    public SerializerAdapter getSerializerAdapter();
}

/**
 * Utility methods for Azure Core functionality.
 */
class CoreUtils {
    /**
     * Checks if a string is null or empty.
     * @param string String to check
     * @return true if string is null or empty
     */
    public static boolean isNullOrEmpty(String string);
    
    /**
     * Gets the first non-null value from the provided options.
     * @param <T> Type of the values
     * @param values Values to check
     * @return First non-null value or null if all are null
     */
    @SafeVarargs
    public static <T> T firstNonNull(T... values);
    
    /**
     * Creates a deep copy of the provided object using serialization.
     * @param <T> Type of the object
     * @param object Object to clone
     * @param clazz Class of the object
     * @return Deep copy of the object
     */
    public static <T> T clone(T object, Class<T> clazz);
    
    /**
     * Gets the application ID from the configuration.
     * @param configuration Configuration instance
     * @return Application ID or null if not configured
     */
    public static String getApplicationId(Configuration configuration);
    
    /**
     * Extracts the error from a Mono or Flux.
     * @param throwable Throwable from reactive stream
     * @return Extracted Throwable
     */
    public static Throwable extractAndWrapException(Throwable throwable);
    
    /**
     * Finds the first throwable in the causal chain that is an instance of the provided class.
     * @param <T> Type of throwable to find
     * @param throwable Root throwable
     * @param clazz Class to search for
     * @return First matching throwable or null
     */
    public static <T extends Throwable> T findFirstOfType(Throwable throwable, Class<T> clazz);
}

/**
 * Utility methods for working with Reactor Flux.
 */
class FluxUtil {
    /**
     * Collects ByteBuffer Flux into a single byte array.
     * @param stream Flux of ByteBuffer
     * @return Mono containing collected byte array
     */
    public static Mono<byte[]> collectBytesInByteBufferStream(Flux<ByteBuffer> stream);
    
    /**
     * Converts a ByteBuffer Flux to a BinaryData.
     * @param stream Flux of ByteBuffer
     * @return Mono containing BinaryData
     */
    public static Mono<BinaryData> toBinaryData(Flux<ByteBuffer> stream);
    
    /**
     * Writes a ByteBuffer Flux to an OutputStream.
     * @param stream Flux of ByteBuffer
     * @param outputStream Target OutputStream
     * @return Mono representing the write operation
     */
    public static Mono<Void> writeToOutputStream(Flux<ByteBuffer> stream, OutputStream outputStream);
    
    /**
     * Creates a Flux that emits after a delay with exponential backoff.
     * @param delay Initial delay
     * @param maxRetries Maximum number of retries
     * @return Flux with exponential backoff
     */
    public static Flux<Long> createExponentialBackoffFlux(Duration delay, int maxRetries);
}

/**
 * Entity tag utility for HTTP caching.
 */
class ETag {
    /**
     * The wildcard ETag.
     */
    public static final ETag ALL = new ETag("*");
    
    /**
     * Creates an ETag.
     * @param eTag ETag string value
     */
    public ETag(String eTag);
    
    /**
     * Gets the ETag value.
     * @return ETag string
     */
    public String toString();
    
    /**
     * Checks if this ETag equals another.
     * @param other Other ETag to compare
     * @return true if equal
     */
    @Override
    public boolean equals(Object other);
    
    /**
     * Gets the hash code.
     * @return Hash code
     */
    @Override
    public int hashCode();
}

/**
 * Builder for constructing URLs.
 */
class UrlBuilder {
    /**
     * Creates a UrlBuilder.
     */
    public UrlBuilder();
    
    /**
     * Sets the scheme (protocol).
     * @param scheme URL scheme
     * @return Updated UrlBuilder
     */
    public UrlBuilder setScheme(String scheme);
    
    /**
     * Sets the host.
     * @param host URL host
     * @return Updated UrlBuilder
     */
    public UrlBuilder setHost(String host);
    
    /**
     * Sets the port.
     * @param port URL port
     * @return Updated UrlBuilder
     */
    public UrlBuilder setPort(int port);
    
    /**
     * Sets the path.
     * @param path URL path
     * @return Updated UrlBuilder
     */
    public UrlBuilder setPath(String path);
    
    /**
     * Adds a query parameter.
     * @param name Parameter name
     * @param value Parameter value
     * @return Updated UrlBuilder
     */
    public UrlBuilder setQueryParameter(String name, String value);
    
    /**
     * Removes a query parameter.
     * @param name Parameter name to remove
     * @return Updated UrlBuilder
     */
    public UrlBuilder removeQueryParameter(String name);
    
    /**
     * Builds the URL.
     * @return Constructed URL
     */
    public URL toURL();
    
    /**
     * Builds the URL string.
     * @return URL as string
     */
    public String toString();
}

/**
 * Iterable stream that can be iterated multiple times.
 */
class IterableStream<T> implements Iterable<T> {
    /**
     * Creates an IterableStream from an Iterable.
     * @param <T> Element type
     * @param iterable Source iterable
     * @return IterableStream instance
     */
    public static <T> IterableStream<T> of(Iterable<T> iterable);
    
    /**
     * Gets an iterator over elements.
     * @return Iterator over elements
     */
    @Override
    public Iterator<T> iterator();
    
    /**
     * Gets a stream of elements.
     * @return Stream of elements
     */
    public Stream<T> stream();
    
    /**
     * Applies a function to each element and returns a new IterableStream.
     * @param <U> Result element type
     * @param mapper Function to apply
     * @return Mapped IterableStream
     */
    public <U> IterableStream<U> map(Function<T, U> mapper);
    
    /**
     * Filters elements based on a predicate.
     * @param predicate Filter predicate
     * @return Filtered IterableStream
     */
    public IterableStream<T> filter(Predicate<T> predicate);
}

/**
 * Continuable page interface for paging operations.
 */
interface ContinuablePage<C, T> {
    /**
     * Gets the continuation token.
     * @return Continuation token or null if no more pages
     */
    C getContinuationToken();
    
    /**
     * Gets the elements on this page.
     * @return Iterable of page elements
     */
    IterableStream<T> getElements();
}

/**
 * Synchronous paged iterable with continuation support.
 */
class ContinuablePagedIterable<C, T> extends PagedIterable<T> {
    /**
     * Gets pages as an iterable with continuation tokens.
     * @return Iterable of pages
     */
    public Iterable<ContinuablePage<C, T>> iterableByPage();
    
    /**
     * Gets pages starting from a continuation token.
     * @param continuationToken Token to start from
     * @return Iterable of pages
     */
    public Iterable<ContinuablePage<C, T>> iterableByPage(C continuationToken);
    
    /**
     * Gets pages with a preferred page size.
     * @param preferredPageSize Preferred number of elements per page
     * @return Iterable of pages
     */
    public Iterable<ContinuablePage<C, T>> iterableByPage(int preferredPageSize);
    
    /**
     * Gets pages starting from a continuation token with preferred page size.
     * @param continuationToken Token to start from
     * @param preferredPageSize Preferred number of elements per page
     * @return Iterable of pages
     */
    public Iterable<ContinuablePage<C, T>> iterableByPage(C continuationToken, int preferredPageSize);
}

/**
 * Asynchronous paged flux with continuation support.
 */
class ContinuablePagedFlux<C, T> extends PagedFlux<T> {
    /**
     * Gets pages as a flux with continuation tokens.
     * @return Flux of pages
     */
    public Flux<ContinuablePage<C, T>> byPage();
    
    /**
     * Gets pages starting from a continuation token.
     * @param continuationToken Token to start from
     * @return Flux of pages
     */
    public Flux<ContinuablePage<C, T>> byPage(C continuationToken);
    
    /**
     * Gets pages with a preferred page size.
     * @param preferredPageSize Preferred number of elements per page
     * @return Flux of pages
     */
    public Flux<ContinuablePage<C, T>> byPage(int preferredPageSize);
    
    /**
     * Gets pages starting from a continuation token with preferred page size.
     * @param continuationToken Token to start from
     * @param preferredPageSize Preferred number of elements per page
     * @return Flux of pages
     */
    public Flux<ContinuablePage<C, T>> byPage(C continuationToken, int preferredPageSize);
}

import com.azure.core.util.Configuration;
import com.azure.core.util.ConfigurationBuilder;

// Using global configuration
Configuration config = Configuration.getGlobalConfiguration();

// Get configuration values with defaults
String endpoint = config.get("AZURE_ENDPOINT", "https://default.azure.com");
int timeout = config.get("TIMEOUT", Integer::parseInt, 30);
boolean enableLogging = config.get("ENABLE_LOGGING", Boolean::parseBoolean, false);

// Programmatically set configuration
config.put("API_VERSION", "2023-01-01")
      .put("MAX_RETRIES", "3");

// Create custom configuration
Configuration customConfig = new ConfigurationBuilder()
    .putConfigurationSource(new MyCustomConfigSource())
    .build();

// Check if configuration exists
if (config.contains("SECRET_KEY")) {
    String secret = config.get("SECRET_KEY");
    // Use secret
}

import com.azure.core.util.Context;

// Create context with metadata
Context context = Context.NONE
    .addData("user-id", "user123")
    .addData("correlation-id", UUID.randomUUID().toString())
    .addData("operation", "create-user");

// Extract data from context
Optional<Object> userId = context.getData("user-id");
String correlationId = (String) context.getData("correlation-id").orElse(null);

// Pass context through operations
httpClient.send(request, context);

// Add HTTP request ID tracking
Context trackedContext = context.setHttpRequestId("req-456");
String requestId = trackedContext.getHttpRequestId();

import com.azure.core.util.logging.ClientLogger;
import com.azure.core.util.logging.LogLevel;

class MyService {
    private static final ClientLogger LOGGER = new ClientLogger(MyService.class);
    
    public void processData(String data) {
        LOGGER.info("Processing data for request: {}", data);
        
        try {
            // Process data
            LOGGER.verbose("Data processing steps completed successfully");
        } catch (Exception e) {
            LOGGER.error("Failed to process data", e);
            throw e;
        }
    }
    
    public void conditionalLogging() {
        if (LOGGER.canLogAtLevel(LogLevel.VERBOSE)) {
            // Expensive operation only if verbose logging is enabled
            String expensiveDebugInfo = computeExpensiveDebugInfo();
            LOGGER.verbose("Debug info: {}", expensiveDebugInfo);
        }
    }
}

import com.azure.core.util.polling.*;
import java.time.Duration;

// Synchronous polling
SyncPoller<OperationStatus, String> poller = // ... create poller

// Poll until completion
PollResponse<OperationStatus> finalResponse = poller.waitForCompletion();

// Poll with timeout
PollResponse<OperationStatus> response = poller.waitForCompletion(Duration.ofMinutes(5));

// Wait for specific status
poller.waitUntil(LongRunningOperationStatus.IN_PROGRESS);

// Get final result
if (finalResponse.getStatus() == LongRunningOperationStatus.SUCCESSFULLY_COMPLETED) {
    String result = poller.getFinalResult();
    System.out.println("Operation completed: " + result);
}

// Asynchronous polling
PollerFlux<OperationStatus, String> asyncPoller = // ... create async poller

asyncPoller.flux()
    .doOnNext(pollResponse -> {
        System.out.println("Current status: " + pollResponse.getStatus());
    })
    .then(asyncPoller.getFinalResult())
    .subscribe(result -> {
        System.out.println("Final result: " + result);
    });

import com.azure.core.util.UrlBuilder;

// Build complex URLs
UrlBuilder builder = new UrlBuilder()
    .setScheme("https")
    .setHost("api.example.com")
    .setPort(443)
    .setPath("/v1/users")
    .setQueryParameter("limit", "50")
    .setQueryParameter("offset", "100")
    .setQueryParameter("filter", "active=true");

URL url = builder.toURL();
String urlString = builder.toString();

// Modify existing URLs
builder.removeQueryParameter("offset")
       .setQueryParameter("sort", "created_date");

import com.azure.core.util.ETag;

// Create ETags
ETag strongETag = new ETag("\"686897696a7c876b7e\"");
ETag weakETag = new ETag("W/\"686897696a7c876b7e\"");
ETag wildcardETag = ETag.ALL;

// Use in conditional requests
HttpRequest request = new HttpRequest(HttpMethod.GET, url);
request.setHeader("If-None-Match", strongETag.toString());

// Compare ETags
if (eTag1.equals(eTag2)) {
    System.out.println("Resources are the same");
}

import com.azure.core.util.CoreUtils;
import com.azure.core.util.FluxUtil;

// String utilities
String value = CoreUtils.firstNonNull(null, "", "default");
boolean isEmpty = CoreUtils.isNullOrEmpty(someString);

// Exception handling
try {
    // Some operation
} catch (Exception e) {
    Throwable rootCause = CoreUtils.findFirstOfType(e, IllegalArgumentException.class);
    if (rootCause != null) {
        // Handle specific exception type
    }
}

// Flux utilities
Flux<ByteBuffer> dataFlux = // ... get data flux
Mono<byte[]> bytes = FluxUtil.collectBytesInByteBufferStream(dataFlux);
Mono<BinaryData> binaryData = FluxUtil.toBinaryData(dataFlux);

// Write to output stream
OutputStream outputStream = // ... get output stream
FluxUtil.writeToOutputStream(dataFlux, outputStream).block();

/**
 * General configuration options for HttpClients.
 */
class HttpClientOptions extends ClientOptions {
    /**
     * Creates a new instance of HttpClientOptions.
     */
    public HttpClientOptions();
    
    /**
     * Sets the proxy options that the HttpClient will use.
     * @param proxyOptions The proxy options to use
     * @return The updated HttpClientOptions object
     */
    public HttpClientOptions setProxyOptions(ProxyOptions proxyOptions);
    
    /**
     * Gets the proxy options that the HttpClient will use.
     * @return The proxy options to use
     */
    public ProxyOptions getProxyOptions();
    
    /**
     * Sets the configuration store that the HttpClient will use.
     * @param configuration The configuration store to use
     * @return The updated HttpClientOptions object
     */
    public HttpClientOptions setConfiguration(Configuration configuration);
    
    /**
     * Gets the configuration store that the HttpClient will use.
     * @return The configuration store to use
     */
    public Configuration getConfiguration();
    
    /**
     * Sets the connection timeout for a request to be sent.
     * @param connectTimeout Connect timeout duration
     * @return The updated HttpClientOptions object
     */
    public HttpClientOptions setConnectTimeout(Duration connectTimeout);
    
    /**
     * Gets the connection timeout for a request to be sent.
     * @return The connection timeout of a request to be sent
     */
    public Duration getConnectTimeout();
    
    /**
     * Sets the writing timeout for a request to be sent.
     * @param writeTimeout Write operation timeout duration
     * @return The updated HttpClientOptions object
     */
    public HttpClientOptions setWriteTimeout(Duration writeTimeout);
    
    /**
     * Gets the writing timeout for a request to be sent.
     * @return The writing timeout of a request to be sent
     */
    public Duration getWriteTimeout();
    
    /**
     * Sets the response timeout duration used when waiting for a server to reply.
     * @param responseTimeout Response timeout duration
     * @return The updated HttpClientOptions object
     */
    public HttpClientOptions setResponseTimeout(Duration responseTimeout);
    
    /**
     * Gets the response timeout duration used when waiting for a server to reply.
     * @return The response timeout duration
     */
    public Duration getResponseTimeout();
    
    /**
     * Sets the read timeout duration used when reading the server response.
     * @param readTimeout Read timeout duration
     * @return The updated HttpClientOptions object
     */
    public HttpClientOptions setReadTimeout(Duration readTimeout);
    
    /**
     * Gets the read timeout duration used when reading the server response.
     * @return The read timeout duration
     */
    public Duration getReadTimeout();
    
    /**
     * Sets the maximum connection pool size used by the underlying HTTP client.
     * @param maximumConnectionPoolSize The maximum connection pool size
     * @return The updated HttpClientOptions object
     */
    public HttpClientOptions setMaximumConnectionPoolSize(Integer maximumConnectionPoolSize);
    
    /**
     * Gets the maximum connection pool size used by the underlying HTTP client.
     * @return The maximum connection pool size
     */
    public Integer getMaximumConnectionPoolSize();
    
    /**
     * Sets the duration of time before an idle connection.
     * @param connectionIdleTimeout The connection idle timeout duration
     * @return The updated HttpClientOptions object
     */
    public HttpClientOptions setConnectionIdleTimeout(Duration connectionIdleTimeout);
    
    /**
     * Gets the duration of time before an idle connection is closed.
     * @return The connection idle timeout duration
     */
    public Duration getConnectionIdleTimeout();
}

/**
 * Interface for close operations that are asynchronous.
 */
interface AsyncCloseable {
    /**
     * Begins the close operation. If one is in progress, will return that existing close operation.
     * @return A Mono representing the close operation
     */
    Mono<Void> closeAsync();
}

/**
 * A generic interface for sending HTTP requests using the provided service version.
 */
interface ServiceVersion {
    /**
     * Gets the string representation of the ServiceVersion.
     * @return the string representation of the ServiceVersion
     */
    String getVersion();
}

/**
 * Utility for building user agent string for Azure client libraries.
 */
class UserAgentUtil {
    /**
     * Default UserAgent header.
     */
    public static final String DEFAULT_USER_AGENT_HEADER = "azsdk-java";
    
    /**
     * Return user agent string for the given sdk name and version.
     * @param applicationId Name of the application
     * @param sdkName Name of the SDK
     * @param sdkVersion Version of the SDK
     * @param configuration The configuration to use to determine if platform info should be included
     * @return User agent string as specified in design guidelines
     */
    public static String toUserAgentString(String applicationId, String sdkName, String sdkVersion,
        Configuration configuration);
}

/**
 * Utility type exposing Base64 encoding and decoding methods.
 */
class Base64Util {
    /**
     * Encodes a byte array to base64.
     * @param src the byte array to encode
     * @return the base64 encoded bytes
     */
    public static byte[] encode(byte[] src);
    
    /**
     * Encodes a byte array to base64 URL format.
     * @param src the byte array to encode
     * @return the base64 URL encoded bytes
     */
    public static byte[] encodeURLWithoutPadding(byte[] src);
    
    /**
     * Encodes a byte array to a base 64 string.
     * @param src the byte array to encode
     * @return the base64 encoded string
     */
    public static String encodeToString(byte[] src);
    
    /**
     * Decodes a base64 encoded byte array.
     * @param encoded the byte array to decode
     * @return the decoded byte array
     */
    public static byte[] decode(byte[] encoded);
    
    /**
     * Decodes a byte array in base64 URL format.
     * @param src the byte array to decode
     * @return the decoded byte array
     */
    public static byte[] decodeURL(byte[] src);
    
    /**
     * Decodes a base64 encoded string.
     * @param encoded the string to decode
     * @return the decoded byte array
     */
    public static byte[] decodeString(String encoded);
}

/**
 * Encodes and decodes using Base64 URL encoding.
 */
class Base64Url {
    /**
     * Creates a new Base64Url object with the specified encoded string.
     * @param string The encoded string
     */
    public Base64Url(String string);
    
    /**
     * Creates a new Base64Url object with the specified encoded bytes.
     * @param bytes The encoded bytes
     */
    public Base64Url(byte[] bytes);
    
    /**
     * Encodes a byte array into Base64Url encoded bytes.
     * @param bytes The byte array to encode
     * @return A new Base64Url instance
     */
    public static Base64Url encode(byte[] bytes);
    
    /**
     * Returns the underlying encoded byte array.
     * @return The underlying encoded byte array
     */
    public byte[] encodedBytes();
    
    /**
     * Decode the bytes and returns its value.
     * @return The decoded byte array
     */
    public byte[] decodedBytes();
    
    /**
     * Gets the string representation.
     * @return String representation of the encoded bytes
     */
    @Override
    public String toString();
}

/**
 * A ProgressListener is an interface that can be used to listen to the progress of I/O transfers.
 */
@FunctionalInterface
interface ProgressListener {
    /**
     * The callback function invoked as progress is reported.
     * @param progress The total progress at the current point of time
     */
    void handleProgress(long progress);
}

/**
 * ProgressReporter offers a convenient way to add progress tracking to I/O operations.
 */
class ProgressReporter {
    /**
     * Creates a ProgressReporter that notifies ProgressListener.
     * @param progressListener The ProgressListener to be notified about progress
     * @return The ProgressReporter instance
     */
    public static ProgressReporter withProgressListener(ProgressListener progressListener);
    
    /**
     * Creates child ProgressReporter that can be used to track sub-progress.
     * @return The child ProgressReporter
     */
    public ProgressReporter createChild();
    
    /**
     * Resets progress to zero and notifies.
     */
    public void reset();
    
    /**
     * Accumulates the provided progress and notifies.
     * @param progress The number to be accumulated
     */
    public void reportProgress(long progress);
}