Update Programming Guide

Programming-Guide.md

@@ -143,12 +143,44 @@ Or clear everything:
 Ctx.INSTANCE.clear();
 ```
 
+## Multiple Named Contexts
+
+You can create and manage multiple independent contexts identified by names.
+
+```java
+// Obtain or create named contexts
+CtxInterface orderCtx = Ctx.INSTANCE.getContext("order");
+CtxInterface userCtx = Ctx.INSTANCE.getContext("user");
+
+// Define keys for each context
+Key<String> orderIdKey = Key.of("orderId", String.class);
+Key<String> userIdKey = Key.of("userId", String.class);
+
+// Put values into separate contexts
+orderCtx.put(orderIdKey, "ORD123");
+userCtx.put(userIdKey, "USR456");
+
+// Retrieve independently
+String orderId = orderCtx.get(orderIdKey);
+String userId = userCtx.get(userIdKey);
+```
+
+You can list all named contexts:
+
+```java
+Set<String> contexts = Ctx.INSTANCE.contextNames();
+System.out.println("Active contexts: " + contexts);
+```
+
+Changes in one context do not affect others, allowing modular isolation of data.
+
 ## Best Practices
 
 * Define your keys as constants to keep them consistent
 * Register listeners in classes that depend on context changes
 * Remove listeners when no longer needed (though weak references help)
-* Use unique key names to avoid collisions
+* Use unique key names to avoid collisions within each context
+* Use multiple contexts to logically separate unrelated data
 
 ## Complete Example
 
@@ -167,5 +199,7 @@ Ctx.INSTANCE.removeListener(temperatureKey, display);
 
 Ctx.INSTANCE.put(temperatureKey, 30); // no notification after listener removed
 ```
+
 ---
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+