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

Signed-off-by: vishalup29 <vishalupadhyay977@gmail.com>

Author: vishalup29

providers/multiprovider/README.md

@@ -1,5 +1,8 @@
 # OpenFeature Multi-Provider for Java
 
+> **Deprecated:** The multi-provider has been moved into the core Java SDK.
+> Please use `dev.openfeature.sdk.providers.multiprovider.MultiProvider` instead.
+
 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.
 

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

@@ -12,12 +12,7 @@
 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.
+ * @deprecated Use the strategy from the core SDK multi-provider package instead.
  */
 @Slf4j
 @NoArgsConstructor

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

@@ -10,9 +10,7 @@
 import lombok.extern.slf4j.Slf4j;
 
 /**
- * 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.
+ * @deprecated Use the strategy from the core SDK multi-provider package instead.
  */
 @Slf4j
 @NoArgsConstructor

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

@@ -7,6 +7,7 @@
 import dev.openfeature.sdk.ProviderEvaluation;
 import dev.openfeature.sdk.Value;
 import dev.openfeature.sdk.exceptions.GeneralError;
+import dev.openfeature.sdk.providers.multiprovider.MultiProvider;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
@@ -21,7 +22,11 @@
 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
 public class MultiProvider extends EventProvider {