diff --git a/src/main/java/com/alibaba/fastjson/parser/DefaultJSONParser.java b/src/main/java/com/alibaba/fastjson/parser/DefaultJSONParser.java
index 248cb020a0..aa7c10f719 100644
--- a/src/main/java/com/alibaba/fastjson/parser/DefaultJSONParser.java
+++ b/src/main/java/com/alibaba/fastjson/parser/DefaultJSONParser.java
@@ -1194,7 +1194,7 @@ public final void parseArray(final Collection array, Object fieldName) {
         ParseContext context = this.context;
         this.setContext(array, fieldName);
         try {
-            for (int i = 0;; ++i) {
+            for (int i = 0; ; ++i) {
                 if (lexer.isEnabled(Feature.AllowArbitraryCommas)) {
                     while (lexer.token() == JSONToken.COMMA) {
                         lexer.nextToken();
@@ -1280,6 +1280,8 @@ public final void parseArray(final Collection array, Object fieldName) {
                     continue;
                 }
             }
+        } catch (ClassCastException e) {
+            throw new JSONException("unkown error", e);
         } finally {
             this.setContext(context);
         }
diff --git a/src/main/java/com/alibaba/fastjson/parser/JSONLexerBase.java b/src/main/java/com/alibaba/fastjson/parser/JSONLexerBase.java
index a0eff3c235..8385912977 100644
--- a/src/main/java/com/alibaba/fastjson/parser/JSONLexerBase.java
+++ b/src/main/java/com/alibaba/fastjson/parser/JSONLexerBase.java
@@ -483,7 +483,7 @@ public final Number integerValue() throws NumberFormatException {
                 }
                 return result;
             } else { /* Only got "-" */
-                throw new NumberFormatException(numberString());
+                throw new JSONException("illegal number format : " + numberString());
             }
         } else {
             result = -result;
@@ -5086,8 +5086,12 @@ private void scanStringSingleQuote() {
      * Append a character to sbuf.
      */
     protected final void putChar(char ch) {
-        if (sp == sbuf.length) {
-            char[] newsbuf = new char[sbuf.length * 2];
+        if (sp >= sbuf.length) {
+            int len = sbuf.length * 2;
+            if (len < sp) {
+                len = sp + 1;
+            }
+            char[] newsbuf = new char[len];
             System.arraycopy(sbuf, 0, newsbuf, 0, sbuf.length);
             sbuf = newsbuf;
         }
diff --git a/src/test/java/com/alibaba/json/bvt/issue_3600/Issue3631.java b/src/test/java/com/alibaba/json/bvt/issue_3600/Issue3631.java
new file mode 100644
index 0000000000..0baaf22ea9
--- /dev/null
+++ b/src/test/java/com/alibaba/json/bvt/issue_3600/Issue3631.java
@@ -0,0 +1,37 @@
+package com.alibaba.json.bvt.issue_3600;
+
+import com.alibaba.fastjson.JSON;
+import com.alibaba.fastjson.JSONException;
+import junit.framework.TestCase;
+
+import java.util.Base64;
+
+public class Issue3631 extends TestCase {
+    public void test_issue_1() throws Exception {
+        try {
+            JSON.parse("{[-");
+        } catch (JSONException unused) {
+            // skip
+        }
+    }
+
+    public void test_issue_2() throws Exception {
+        try {
+            JSON.parse("TreeSet[[]");
+        } catch (JSONException unused) {
+            // skip
+        }
+    }
+
+    public void test_issue_3() throws Exception {
+        try {
+            JSON.parse(btoa("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"));
+        } catch (JSONException unused) {
+            // skip
+        }
+    }
+
+    public static String btoa(String base64) {
+        return new String(Base64.getDecoder().decode(base64));
+    }
+}