update and getbyid added

src/main/java/com/socialmedia/controller/BalanceController.java

@@ -1,8 +1,8 @@
 package com.socialmedia.controller;
 
 import java.util.List;
-
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.*;
 import com.socialmedia.model.Balance;
 import com.socialmedia.service.BalanceService;
@@ -22,5 +22,17 @@ public Balance createBalance(@RequestBody Balance balanceRequest) {
     public List<Balance> getAllBalances() {
         return balanceService.findAllBalances();
     }
+
+    //@PathVariable long id extracts id from URL and pass it to method.
+        @GetMapping("/{id}")
+        public Balance getBalance(@PathVariable("id")Long id) {
+            return balanceService.findBalanceById(id);
+        }
+
+
+    @PutMapping("/{id}")
+    public Balance updateBalance(@PathVariable("id") Long id, @RequestBody Balance balanceRequest) {
+        return balanceService.updateBalance(id, balanceRequest);
+    }
 
 }

src/main/java/com/socialmedia/repository/BalanceRepository.java

@@ -24,7 +24,23 @@ public Balance save(Balance balance) {
 	 public List<Balance> findAll() {
 	        return new ArrayList<>(balanceMap.values());
 	    }
-
+
+	 //fetch the balance with that id
+	 public Balance findById(Long id) {
+		    return balanceMap.get(id);
+		}
+
+	 public Balance update(Long id, Balance balance) {
+	        Balance existing = balanceMap.get(id);
+	        if (existing != null) {
+	            existing.setAccountHolder(balance.getAccountHolder());
+	            existing.setAmount(balance.getAmount());
+	            balanceMap.put(id, existing);
+	            return existing;
+	        }
+	        return null; 
+	    }
+
 	}
 
 

src/main/java/com/socialmedia/service/BalanceService.java

@@ -19,8 +19,14 @@ public Balance create(Balance balance) {
 
     public List<Balance> findAllBalances() {
         return balanceRepository.findAll();
-
     }
+    public Balance findBalanceById(Long id) {
+        return balanceRepository.findById(id);
+    }
+    public Balance updateBalance(Long id, Balance balance) {
+        return balanceRepository.update(id, balance);
+    }
+
 }