Strange issue with POF: byte array with the value 94

Question

This is a somewhat strange issue we’ve managed to reduce to this test case. We’ve also seen similar issues with chars and shorts as well. It’s only a problem if the byte value inside the byte array is equal to 94! A value of 93, 95, etc, seems to be ok.
Given the below class, the byte values both in the array and the single byte value are wrong when deserializing. The value inside the byte array isn’t what we put in (get [75] instead of [94]) and the single byte value is null (not 114).
Pof object code:
package com.test;
import java.io.IOException;
import java.util.Arrays;
import com.tangosol.io.pof.PofReader;
import com.tangosol.io.pof.PofWriter;
import com.tangosol.io.pof.PortableObject;
public class PofObject1 implements PortableObject {
     private byte[] byteArray;
     private byte byteValue;
     public void setValues() {
          byteArray = new byte[] {94};
          byteValue = 114;
     @Override
     public void readExternal(PofReader reader) throws IOException {
          Object byteArray = reader.readObjectArray(0, null);
          Object byteValue = reader.readObject(1);
          System.out.println(Arrays.toString((Object[])byteArray));
          System.out.println(byteValue);
          if (byteValue == null) throw new IOException("byteValue is null!");
     @Override
     public void writeExternal(PofWriter writer) throws IOException {
          writer.writeObject(0, byteArray);
          writer.writeObject(1, byteValue);
Using writer.writeObjectArray(0, byteArray); instead of writer.writeObject(0, byteArray); doesn't help. In this case byteArray would be of type Object[] (as accessed through reflection).
This is simply put in to a distributed cache and then fetched back. No EPs, listeners or stuff like that involved:
     public static void main(String... args) throws Exception {
          NamedCache cache = CacheFactory.getCache("my-cache");
          PofObject1 o = new PofObject1();
          o.setValues();
          cache.put("key1", o);
          cache.get("key1");
Only tried it with Coherecne 3.7.1.3.
Cache config file:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE cache-config SYSTEM "cache-config.dtd">
<cache-config>
     <caching-scheme-mapping>
          <cache-mapping>
               <cache-name>my-cache</cache-name>
               <scheme-name>my-cache</scheme-name>
          </cache-mapping>
     </caching-scheme-mapping>
     <caching-schemes>
          <distributed-scheme>
               <scheme-name>my-cache</scheme-name>
               <service-name>my-cache</service-name>
               <serializer>
                    <class-name>
                         com.tangosol.io.pof.ConfigurablePofContext
                    </class-name>
                    <init-params>
                         <init-param>
                              <param-type>string</param-type>
                              <param-value>pof-config.xml</param-value>
                         </init-param>
                    </init-params>
               </serializer>
               <lease-granularity>thread</lease-granularity>
               <thread-count>10</thread-count>
               <backing-map-scheme>
                    <local-scheme>
                    </local-scheme>
               </backing-map-scheme>
               <autostart>true</autostart>
          </distributed-scheme>
     </caching-schemes>
</cache-config>
POF config file:
<?xml version="1.0"?>
<pof-config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xmlns="http://xmlns.oracle.com/coherence/coherence-pof-config"
     xsi:schemaLocation="http://xmlns.oracle.com/coherence/coherence-pof-config coherence-pof-config.xsd">
     <user-type-list>
          <!-- coherence POF user types -->
          <include>coherence-pof-config.xml</include>
          <user-type>
               <type-id>1460</type-id>
               <class-name>com.test.PofObject1</class-name>
          </user-type>
     </user-type-list>
</pof-config>

Answer 1

Hi,
POF uses certain byte values as an optimization to represent well known values of certain Object types - e.g. boolean True and False, some very small numbers, null etc... When you do read/write Object instead of using the correct method I suspect POF gets confused over the type and value that the field should be.
There are a number of cases where POF does not know what the type is - Numbers would be one of these, for example if I stored a long of value 10 on deserialization POF would not know if that was an int, long double etc... so you have to use the correct method to get it back. Collections are another - If you serialize a Set all POF knows is that you have serialized some sort of Collection so unless you are specific when deserializing you will get back a List.
JK