Issue open-feature/java-sdk#1486 Deprecate contrib multi-provider and redirect users to SDK implementation.

Signed-off-by: vishalup29 <[email protected]>

Author: vishalup29

providers/multiprovider/README.md

@@ -1,5 +1,9 @@
 # OpenFeature Multi-Provider for Java
 
+> **Deprecated:** This module has been superseded by the multi-provider implementation in the **core Java SDK**.  
+> For new projects, please use  [`dev.openfeature.sdk.multiprovider.MultiProvider`](https://github.com/open-feature/java-sdk/blob/main/src/main/java/dev/openfeature/sdk/multiprovider/MultiProvider.java) from the core SDK instead of this contrib module.  
+> This artifact remains available for backwards compatibility but may be removed in a future release.
+
 The OpenFeature Multi-Provider wraps multiple underlying providers in a unified interface, allowing the SDK client to transparently interact with all those providers at once.
 This allows use cases where a single client and evaluation interface is desired, but where the flag data should come from more than one source.
 
@@ -14,6 +18,11 @@ Some examples:
   You can use the Multi-Provider to automatically fall back to a local configuration if an external vendor provider goes down, rather than using the default values.
   By using the FirstSuccessfulStrategy, the Multi-Provider will move on to the next provider in the list if an error is thrown.
 
+> **Recommended replacement:** For new integrations, see the multi-provider in the core SDK:
+>
+> - Class: [`dev.openfeature.sdk.multiprovider.MultiProvider`](https://github.com/open-feature/java-sdk/blob/main/src/main/java/dev/openfeature/sdk/multiprovider/MultiProvider.java)
+> - Documentation: refer to the [Java SDK README](https://github.com/open-feature/java-sdk#openfeature-java-sdk) Javadoc.
+
 ## Strategies
 
 The Multi-Provider supports multiple ways of deciding how to evaluate the set of providers it is managing, and how to deal with any errors that are thrown.
@@ -49,6 +58,9 @@ Rather than making assumptions about when to use a provider’s result and when
 
 ## Installation
 
+> **Note:** The following coordinates are kept for existing users of the contrib multi-provider.  
+> New projects should prefer the core SDK dependency and its `dev.openfeature.sdk.providers.multiprovider.MultiProvider` implementation.
+
 <!-- x-release-please-start-version -->
 
 ```xml
@@ -63,6 +75,8 @@ Rather than making assumptions about when to use a provider’s result and when
 <!-- x-release-please-end-version -->
 
 ## Usage
+Legacy usage: This example shows how to use the contrib multi-provider.
+For new code, use dev.openfeature.sdk.providers.multiprovider.MultiProvider from the core SDK and follow the examples in the Java SDK README.
 
 Usage example:
 

providers/multiprovider/src/main/java/dev/openfeature/contrib/providers/multiprovider/FirstMatchStrategy.java

@@ -12,15 +12,15 @@
 import lombok.extern.slf4j.Slf4j;
 
 /**
- * First match strategy. Return the first result returned by a provider. Skip providers that
- * indicate they had no value due to FLAG_NOT_FOUND. In all other cases, use the value returned by
- * the provider. If any provider returns an error result other than FLAG_NOT_FOUND, the whole
- * evaluation should error and “bubble up” the individual provider’s error in the result. As soon as
- * a value is returned by a provider, the rest of the operation should short-circuit and not call
- * the rest of the providers.
+ /**
+ * First Match Strategy. Evaluates providers until one returns a value or an error is thrown.
+ *
+ * @deprecated Use {@link dev.openfeature.sdk.providers.multiprovider.FirstMatchStrategy}
+ * from the core SDK instead.
  */
 @Slf4j
 @NoArgsConstructor
+@Deprecated
 public class FirstMatchStrategy implements Strategy {
 
     /**

providers/multiprovider/src/main/java/dev/openfeature/contrib/providers/multiprovider/FirstSuccessfulStrategy.java

@@ -11,11 +11,14 @@
 
 /**
  * First Successful Strategy. Similar to “First Match”, except that errors from evaluated providers
- * do not halt execution. Instead, it will return the first successful result from a provider. If no
- * provider successfully responds, it will throw an error result.
+ * do not halt execution. Instead, it returns the first successful result from a provider.
+ *
+ * @deprecated Use {@link dev.openfeature.sdk.providers.multiprovider.FirstSuccessfulStrategy}
+ * from the core SDK instead.
  */
 @Slf4j
 @NoArgsConstructor
+@Deprecated
 public class FirstSuccessfulStrategy implements Strategy {
 
     @Override

providers/multiprovider/src/main/java/dev/openfeature/contrib/providers/multiprovider/MultiProvider.java

@@ -21,8 +21,13 @@
 import lombok.extern.slf4j.Slf4j;
 import org.json.JSONObject;
 
-/** Provider implementation for Multi-provider. */
+/**
+ * @deprecated
+ * Use {@link dev.openfeature.sdk.providers.multiprovider.MultiProvider}
+ * from the core SDK instead.
+ */
 @Slf4j
+@Deprecated
 public class MultiProvider extends EventProvider {
 
     @Getter

providers/multiprovider/src/main/java/dev/openfeature/contrib/providers/multiprovider/Strategy.java

@@ -6,7 +6,13 @@
 import java.util.Map;
 import java.util.function.Function;
 
-/** strategy. */
+/**
+ * Strategy for evaluating flags across multiple providers.
+ *
+ * @deprecated Use strategies from {@link dev.openfeature.sdk.providers.multiprovider}
+ * in the core SDK instead.
+ */
+@Deprecated
 public interface Strategy {
     <T> ProviderEvaluation<T> evaluate(
             Map<String, FeatureProvider> providers,