[Backport] 8234059: Stress test fails with "Unexpected Exception in t…

…hread JFR Event Stream"

Summary:

Test Plan: jdk/jfr

Reviewed-by: yuleil

Issue: dragonwell-project/dragonwell8#112

src/share/classes/jdk/jfr/internal/consumer/ConstantMap.java

@@ -25,6 +25,10 @@
 
 package jdk.jfr.internal.consumer;
 
+import jdk.jfr.internal.LogLevel;
+import jdk.jfr.internal.LogTag;
+import jdk.jfr.internal.Logger;
+
 import jdk.jfr.internal.LongMap;
 
 /**
@@ -90,14 +94,14 @@ Object get(long id) {
             return new Reference(this, id);
         }
 
-        // should always have a value
+        // should ideally always have a value
         Object value = objects.get(id);
         if (value == null) {
-            // unless is 0 which is used to represent null
-            if (id == 0) {
-                return null;
+            // unless id is 0 which is used to represent null
+            if (id != 0) {
+                Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.INFO, "Missing object id=" + id + " in pool " + name + ". All ids should reference an object");
             }
-            throw new InternalError("Missing object id=" + id + " in pool " + name + ". All ids should reference object");
+            return null;
         }
 
         // id is resolved (but not the whole pool)