diff --git a/src/hotspot/share/classfile/systemDictionary.cpp b/src/hotspot/share/classfile/systemDictionary.cpp
index f482a5bb303..c1459e81f7b 100644
--- a/src/hotspot/share/classfile/systemDictionary.cpp
+++ b/src/hotspot/share/classfile/systemDictionary.cpp
@@ -1768,6 +1768,14 @@ void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int
     ResolutionErrorEntry* entry = ResolutionErrorTable::find_entry(pool, which);
     if (entry == nullptr) {
       ResolutionErrorTable::add_entry(pool, which, error, message, cause, cause_msg);
+    } else {
+      ResourceMark rm;
+      guarantee(entry->error() != nullptr, "null error for error %s message %s cause %s cause_msg %s nest_host_error %s",
+                error ? error->as_C_string() : "null",
+                message ? message : "null",
+                cause ? cause->as_C_string() : "null",
+                cause_msg ? cause_msg : "null",
+                entry->nest_host_error() != nullptr ? entry->nest_host_error() : "null");
     }
   }
 }
@@ -1789,8 +1797,11 @@ Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool,
       *message = entry->message();
       *cause = entry->cause();
       *cause_msg = entry->cause_msg();
+      guarantee(entry->error() != nullptr, "null error for message %s cause_msg %s nest_host_error %s", entry->message() ? entry->message() : "null",
+                entry->cause_msg() ? entry->cause_msg() : "null", entry->nest_host_error() ? entry->nest_host_error() : "null");
       return entry->error();
     } else {
+      guarantee(false, "%s @ %d %s", pool->pool_holder()->external_name(), which, pool->printable_name_at(which));
       return nullptr;
     }
   }
diff --git a/src/hotspot/share/oops/constantPool.cpp b/src/hotspot/share/oops/constantPool.cpp
index 3223c56628e..8dde4c4a92b 100644
--- a/src/hotspot/share/oops/constantPool.cpp
+++ b/src/hotspot/share/oops/constantPool.cpp
@@ -1976,8 +1976,6 @@ int ConstantPool::find_matching_operand(int pattern_i,
 } // end find_matching_operand()
 
 
-#ifndef PRODUCT
-
 const char* ConstantPool::printable_name_at(int cp_index) {
 
   constantTag tag = tag_at(cp_index);
@@ -1992,9 +1990,6 @@ const char* ConstantPool::printable_name_at(int cp_index) {
   return "";
 }
 
-#endif // PRODUCT
-
-
 // Returns size of constant pool entry.
 jint ConstantPool::cpool_entry_size(jint idx) {
   switch(tag_at(idx).value()) {
diff --git a/src/hotspot/share/oops/constantPool.hpp b/src/hotspot/share/oops/constantPool.hpp
index be4a7a474d4..417bfa55961 100644
--- a/src/hotspot/share/oops/constantPool.hpp
+++ b/src/hotspot/share/oops/constantPool.hpp
@@ -794,7 +794,7 @@ class ConstantPool : public Metadata {
   int pre_resolve_shared_klasses(TRAPS);
 
   // Debugging
-  const char* printable_name_at(int cp_index) PRODUCT_RETURN_NULL;
+  const char* printable_name_at(int cp_index);
 
  private: