improved compatible, fix #3544

src/main/java/com/alibaba/fastjson/parser/deserializer/MapDeserializer.java

@@ -85,6 +85,13 @@ public static Map parseMap(DefaultJSONParser parser, Map<String, Object> map, Ty
 
         int token = lexer.token();
         if (token != JSONToken.LBRACE) {
+            if (token == JSONToken.LITERAL_STRING) {
+                String stringVal = lexer.stringVal();
+                if (stringVal.length() == 0 || stringVal.equals("null")) {
+                    return null;
+                }
+            }
+
             String msg = "syntax error, expect {, actual " + lexer.tokenName();
             if (fieldName instanceof String) {
                 msg += ", fieldName ";

src/test/java/com/alibaba/json/bvt/issue_3500/Issue3544.java

@@ -0,0 +1,27 @@
+package com.alibaba.json.bvt.issue_3500;
+
+import com.alibaba.fastjson.JSON;
+import junit.framework.TestCase;
+import lombok.Getter;
+import lombok.Setter;
+
+import java.util.Map;
+
+public class Issue3544 extends TestCase {
+
+    public void test_errorType() {
+        assertNull("", JSON.toJavaObject(
+                JSON.parseObject("{\"result\":\"\"}"), TestVO.class).result);
+
+        assertNull("", JSON.toJavaObject(
+                JSON.parseObject("{\"result\":\"null\"}"), TestVO.class).result);
+    }
+
+    @Getter
+    @Setter
+    static class TestVO {
+
+        Map<String, String> result;
+
+    }
+}