From 6ce88730f15ab3a86f2bd84e2b48978734dc8b8d Mon Sep 17 00:00:00 2001
From: Larry Cable <larry.cable@yahoo.com>
Date: Mon, 5 Jan 2026 11:21:39 -0800
Subject: [PATCH] JDK-8327246: Add a jcmd diagnostic command to list the jar
 files loaded by a process

---
 src/hotspot/share/oops/instanceKlass.cpp      | 40 ++++++++++++++++++-
 src/hotspot/share/oops/instanceKlass.hpp      |  3 +-
 .../share/services/diagnosticCommand.cpp      | 11 +++--
 .../share/services/diagnosticCommand.hpp      |  3 +-
 4 files changed, 49 insertions(+), 8 deletions(-)

diff --git a/src/hotspot/share/oops/instanceKlass.cpp b/src/hotspot/share/oops/instanceKlass.cpp
index 56a80daed60..2b1b279bfac 100644
--- a/src/hotspot/share/oops/instanceKlass.cpp
+++ b/src/hotspot/share/oops/instanceKlass.cpp
@@ -35,6 +35,7 @@
 #include "classfile/classLoaderData.inline.hpp"
 #include "classfile/javaClasses.hpp"
 #include "classfile/moduleEntry.hpp"
+#include "classfile/symbolTable.hpp"
 #include "classfile/systemDictionary.hpp"
 #include "classfile/systemDictionaryShared.hpp"
 #include "classfile/verifier.hpp"
@@ -2336,8 +2337,8 @@ Method* InstanceKlass::lookup_method_in_all_interfaces(Symbol* name,
   return nullptr;
 }
 
-PrintClassClosure::PrintClassClosure(outputStream* st, bool verbose)
-  :_st(st), _verbose(verbose) {
+PrintClassClosure::PrintClassClosure(outputStream* st, bool verbose, bool location)
+  :_st(st), _verbose(verbose), _location(location) {
   ResourceMark rm;
   _st->print("%-18s  ", "KlassAddr");
   _st->print("%-4s  ", "Size");
@@ -2375,6 +2376,41 @@ void PrintClassClosure::do_klass(Klass* k)  {
   _st->print("%-7s  ", buf);
   // klass name
   _st->print("%-5s  ", k->external_name());
+
+  if (k->is_instance_klass() && _location) {
+
+    oop pd = java_lang_Class::protection_domain(k->java_mirror());
+
+    InstanceKlass* ik;
+
+    if (pd != nullptr && (ik = InstanceKlass::cast(pd->klass()))->is_instance_klass()) {
+
+      TempNewSymbol css  = SymbolTable::new_symbol("codesource");
+      TempNewSymbol csss = SymbolTable::new_symbol("Ljava/security/CodeSource;");
+
+      fieldDescriptor csfd;
+
+      if (ik->find_field(css, csss, &csfd)) {
+
+        oop cs = pd->obj_field(csfd.offset());
+
+        if (cs != nullptr && (ik = InstanceKlass::cast(cs->klass()))->is_instance_klass()) {
+          fieldDescriptor locfd;
+
+          TempNewSymbol csls  = SymbolTable::new_symbol("locationNoFragString");
+          TempNewSymbol cslss = SymbolTable::new_symbol("Ljava/lang/String;");
+
+          if (ik->find_field(csls, cslss, &locfd)) {
+            oop loc = cs->obj_field(locfd.offset());
+
+            if (loc != nullptr && loc->klass() == vmClasses::String_klass()) {
+              java_lang_String::print(loc, _st, MAXPATHLEN);
+            }
+          }
+        }
+      }
+    }
+  }
   // end
   _st->cr();
   if (_verbose) {
diff --git a/src/hotspot/share/oops/instanceKlass.hpp b/src/hotspot/share/oops/instanceKlass.hpp
index 23a59d26093..865fe4d58fa 100644
--- a/src/hotspot/share/oops/instanceKlass.hpp
+++ b/src/hotspot/share/oops/instanceKlass.hpp
@@ -1209,8 +1209,9 @@ class PrintClassClosure : public KlassClosure {
 private:
   outputStream* _st;
   bool _verbose;
+  bool _location;
 public:
-  PrintClassClosure(outputStream* st, bool verbose);
+  PrintClassClosure(outputStream* st, bool verbose, bool location);
 
   void do_klass(Klass* k);
 };
diff --git a/src/hotspot/share/services/diagnosticCommand.cpp b/src/hotspot/share/services/diagnosticCommand.cpp
index 0846f339227..755192c23fa 100644
--- a/src/hotspot/share/services/diagnosticCommand.cpp
+++ b/src/hotspot/share/services/diagnosticCommand.cpp
@@ -958,27 +958,30 @@ ClassesDCmd::ClassesDCmd(outputStream* output, bool heap) :
            "C = marked with @Contended annotation, "
            "R = has been redefined, "
            "S = is shared class",
-           "BOOLEAN", false, "false") {
+           "BOOLEAN", false, "false"),
+  _location("-location", "print class file location url (if available)", "BOOLEAN", false, "false") {
   _dcmdparser.add_dcmd_option(&_verbose);
+  _dcmdparser.add_dcmd_option(&_location);
 }
 
 class VM_PrintClasses : public VM_Operation {
 private:
   outputStream* _out;
   bool _verbose;
+  bool _location;
 public:
-  VM_PrintClasses(outputStream* out, bool verbose) : _out(out), _verbose(verbose) {}
+  VM_PrintClasses(outputStream* out, bool verbose, bool location) : _out(out), _verbose(verbose), _location(location) {}
 
   virtual VMOp_Type type() const { return VMOp_PrintClasses; }
 
   virtual void doit() {
-    PrintClassClosure closure(_out, _verbose);
+    PrintClassClosure closure(_out, _verbose, _location);
     ClassLoaderDataGraph::classes_do(&closure);
   }
 };
 
 void ClassesDCmd::execute(DCmdSource source, TRAPS) {
-  VM_PrintClasses vmop(output(), _verbose.value());
+  VM_PrintClasses vmop(output(), _verbose.value(), _location.value());
   VMThread::execute(&vmop);
 }
 
diff --git a/src/hotspot/share/services/diagnosticCommand.hpp b/src/hotspot/share/services/diagnosticCommand.hpp
index c41e7bf2e2e..d0c3473535f 100644
--- a/src/hotspot/share/services/diagnosticCommand.hpp
+++ b/src/hotspot/share/services/diagnosticCommand.hpp
@@ -737,8 +737,9 @@ public:
 class ClassesDCmd : public DCmdWithParser {
 protected:
   DCmdArgument<bool> _verbose;
+  DCmdArgument<bool> _location;
 public:
-  static int num_arguments() { return 1; }
+  static int num_arguments() { return 2; }
   ClassesDCmd(outputStream* output, bool heap);
   static const char* name() {
     return "VM.classes";