fix(api): use httpMaxMessageSize in checkBodySize instead of gRPC limit

checkBodySize() was enforcing maxMessageSize (gRPC limit) instead of
httpMaxMessageSize, causing the independent HTTP size setting to be
ineffective at the servlet layer.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: bladehan1

framework/src/main/java/org/tron/core/services/http/Util.java

@@ -330,8 +330,9 @@ public static Transaction packTransaction(String strTransaction, boolean selfTyp
   @Deprecated
   public static void checkBodySize(String body) throws Exception {
     CommonParameter parameter = Args.getInstance();
-    if (body.getBytes().length > parameter.getMaxMessageSize()) {
-      throw new Exception("body size is too big, the limit is " + parameter.getMaxMessageSize());
+    if (body.getBytes().length > parameter.getHttpMaxMessageSize()) {
+      throw new Exception("body size is too big, the limit is "
+          + parameter.getHttpMaxMessageSize());
     }
   }
 

framework/src/test/java/org/tron/core/services/http/UtilTest.java

@@ -129,6 +129,32 @@ public void testPackTransactionWithInvalidType() {
         txSignWeight.getResult().getMessage());
   }
 
+  @Test
+  public void testCheckBodySizeUsesHttpLimit() throws Exception {
+    int originalHttpMax = Args.getInstance().getHttpMaxMessageSize();
+    int originalRpcMax = Args.getInstance().getMaxMessageSize();
+    try {
+      // set httpMaxMessageSize larger than maxMessageSize
+      Args.getInstance().setHttpMaxMessageSize(200);
+      Args.getInstance().setMaxMessageSize(100);
+
+      String withinHttpLimit = new String(new char[150]).replace('\0', 'a');
+      // should pass: 150 < httpMaxMessageSize(200), even though > maxMessageSize(100)
+      Util.checkBodySize(withinHttpLimit);
+
+      String exceedsHttpLimit = new String(new char[201]).replace('\0', 'b');
+      try {
+        Util.checkBodySize(exceedsHttpLimit);
+        Assert.fail("expected exception for body exceeding httpMaxMessageSize");
+      } catch (Exception e) {
+        Assert.assertTrue(e.getMessage().contains("200"));
+      }
+    } finally {
+      Args.getInstance().setHttpMaxMessageSize(originalHttpMax);
+      Args.getInstance().setMaxMessageSize(originalRpcMax);
+    }
+  }
+
   @Test
   public void testPackTransaction() {
     String strTransaction = "{\n"