diff --git a/src/java.base/share/classes/java/io/ObjectInputStream.java b/src/java.base/share/classes/java/io/ObjectInputStream.java
index 78008081f..a77a5d5b6 100644
--- a/src/java.base/share/classes/java/io/ObjectInputStream.java
+++ b/src/java.base/share/classes/java/io/ObjectInputStream.java
@@ -306,6 +306,23 @@ public class ObjectInputStream
             filterLogger = (filterLog.isLoggable(Logger.Level.DEBUG)
                     || filterLog.isLoggable(Logger.Level.TRACE)) ? filterLog : null;
         }
+
+        /*
+         * Logger for FastSerializer.
+         * Setup the FastSerializer logger if it is set to DEBUG.
+         * (Assuming it will not change).
+         */
+        static final System.Logger fastSerLogger;
+
+        static {
+            if (printFastSerializer) {
+                Logger fastSerLog = System.getLogger("fastSerializer");
+                fastSerLogger = (fastSerLog.isLoggable(Logger.Level.DEBUG))
+                        ? fastSerLog : null;
+            } else {
+                fastSerLogger = null;
+            }
+        }
     }
 
     /** filter stream for handling block data conversion */
@@ -366,6 +383,14 @@ public class ObjectInputStream
             new sun.security.action.GetBooleanAction(
                     "fastSerializerEscapeMode")).booleanValue();
 
+    /**
+     *  value of  "printFastSerializer" property,
+     *  as true or false for printing FastSerializer logs.
+     */
+    private static final boolean printFastSerializer = java.security.AccessController.doPrivileged(
+            new sun.security.action.GetBooleanAction(
+                    "printFastSerializer")).booleanValue();
+
     /**
      * Creates an ObjectInputStream that reads from the specified InputStream.
      * A serialization stream header is read from the stream and verified.
@@ -988,7 +1013,7 @@ public class ObjectInputStream
             if (s0 != STREAM_MAGIC_FAST || s1 != STREAM_VERSION) {
                 if (s0 != STREAM_MAGIC) {
                     throw new StreamCorruptedException(
-                            String.format("invalid stream header: %04X%04X", s0, s1));
+                            String.format("invalid stream header: %04X%04X, and FastSerializer is activated", s0, s1));
                 }
 
                 if (!fastSerializerEscapeMode) {
@@ -999,10 +1024,18 @@ public class ObjectInputStream
 
                 // Escape to default serialization
                 useFastSerializer = false;
+                if (Logging.fastSerLogger != null) {
+                    Logging.fastSerLogger.log(Logger.Level.DEBUG, "[Deserialize]: Escape and disable FastSerializer");
+                }
             }
         } else if (s0 != STREAM_MAGIC || s1 != STREAM_VERSION) {
+            if (s0 == STREAM_MAGIC_FAST && s1 == STREAM_VERSION) {
+                throw new StreamCorruptedException(
+                        String.format("invalid stream header: %04X%04X, and it is a FastSerializer stream", s0, s1));
+            } else {
                 throw new StreamCorruptedException(
                         String.format("invalid stream header: %04X%04X", s0, s1));
+            }
         }
     }
 
@@ -2129,6 +2162,12 @@ public class ObjectInputStream
         handles.finish(descHandle);
         passHandle = descHandle;
 
+        if (Logging.fastSerLogger != null) {
+            Logging.fastSerLogger.log(Logger.Level.DEBUG,
+                "[Deserialize] useFastSerializer:{0}, Class name:{1}, SerialVersionUID:{2}, flags:{3}",
+                useFastSerializer, desc.getName(), desc.getSerialVersionUID(), desc.getFlags(this));
+        }
+
         return desc;
     }
 
diff --git a/src/java.base/share/classes/java/io/ObjectOutputStream.java b/src/java.base/share/classes/java/io/ObjectOutputStream.java
index 044924593..8935e61dc 100644
--- a/src/java.base/share/classes/java/io/ObjectOutputStream.java
+++ b/src/java.base/share/classes/java/io/ObjectOutputStream.java
@@ -170,6 +170,25 @@ public class ObjectOutputStream
             };
     }
 
+    private static class Logging {
+        /*
+         * Logger for FastSerializer.
+         * Setup the FastSerializer logger if it is set to DEBUG.
+         * (Assuming it will not change).
+         */
+        static final System.Logger fastSerLogger;
+
+        static {
+            if (printFastSerializer) {
+                System.Logger fastSerLog = System.getLogger("fastSerializer");
+                fastSerLogger = (fastSerLog.isLoggable(System.Logger.Level.DEBUG))
+                        ? fastSerLog : null;
+            } else {
+                fastSerLogger = null;
+            }
+        }
+    }
+
     /** filter stream for handling block data conversion */
     private final BlockDataOutputStream bout;
     /** obj -> wire handle map */
@@ -210,6 +229,13 @@ public class ObjectOutputStream
      * on when it is true.
      */
     private static final boolean useFastSerializer = UNSAFE.getUseFastSerializer();
+    /**
+     *  value of  "printFastSerializer" property,
+     *  as true or false for printing FastSerializer logs.
+     */
+    private static final boolean printFastSerializer = java.security.AccessController.doPrivileged(
+            new sun.security.action.GetBooleanAction(
+                    "printFastSerializer")).booleanValue();

     /**
      * Creates an ObjectOutputStream that writes to the specified OutputStream.
@@ -1266,6 +1292,12 @@ public class ObjectOutputStream
         bout.writeByte(TC_CLASSDESC);
         handles.assign(unshared ? null : desc);

+       if (Logging.fastSerLogger != null) {
+            Logging.fastSerLogger.log(System.Logger.Level.DEBUG,
+            "[Serialize]   useFastSerializer:{0}, Class name:{1}, SerialVersionUID:{2}, flags:{3}, protocol:{4}",
+            useFastSerializer, desc.getName(), desc.getSerialVersionUID(), desc.getFlags(this), protocol);
+        }
+
         if (protocol == PROTOCOL_VERSION_1) {
             // do not invoke class descriptor write hook with old protocol
             if (useFastSerializer) {
diff --git a/src/java.base/share/classes/java/io/ObjectStreamClass.java b/src/java.base/share/classes/java/io/ObjectStreamClass.java
index ac3a92bef..a5d7d2d75 100644
--- a/src/java.base/share/classes/java/io/ObjectStreamClass.java
+++ b/src/java.base/share/classes/java/io/ObjectStreamClass.java
@@ -270,6 +270,40 @@ public class ObjectStreamClass implements Serializable {
         return suid.longValue();
     }
 
+    /**
+     * Return the flags for this class described by this descriptor. The flags
+     * means a set of bit masks for ObjectStreamClass, which indicate the status
+     * of SC_WRITE_METHOD, SC_SERIALIZABLE, SC_EXTERNALIZABLE, SC_BLOCK_DATA and
+     * SC_ENUM.
+     *
+     * @param serialStream ObjectOutputStream or ObjectInputStream
+     *
+     * @return the flags for this class described by this descriptor
+     */
+    public byte getFlags(Object serialStream) {
+        byte flags = 0;
+        if (externalizable) {
+            flags |= ObjectStreamConstants.SC_EXTERNALIZABLE;
+            if (serialStream instanceof ObjectOutputStream) {
+                int protocol = ((ObjectOutputStream)serialStream).getProtocolVersion();
+                if (protocol != ObjectStreamConstants.PROTOCOL_VERSION_1) {
+                    flags |= ObjectStreamConstants.SC_BLOCK_DATA;
+                }
+            } else if (serialStream instanceof ObjectInputStream) {
+                flags |= ObjectStreamConstants.SC_BLOCK_DATA;
+            }
+        } else if (serializable) {
+            flags |= ObjectStreamConstants.SC_SERIALIZABLE;
+        }
+        if (hasWriteObjectData) {
+            flags |= ObjectStreamConstants.SC_WRITE_METHOD;
+        }
+        if (isEnum) {
+            flags |= ObjectStreamConstants.SC_ENUM;
+        }
+        return flags;
+    }
+
     /**
      * Return the class in the local VM that this version is mapped to.  Null
      * is returned if there is no corresponding local class.
-- 
2.19.0