1 /*
   2  * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "classfile/classLoaderData.inline.hpp"
  27 #include "classfile/dictionary.inline.hpp"
  28 #include "classfile/protectionDomainCache.hpp"
  29 #include "classfile/systemDictionary.hpp"
  30 #include "classfile/systemDictionaryShared.hpp"
  31 #include "logging/log.hpp"
  32 #include "logging/logStream.hpp"
  33 #include "memory/iterator.hpp"
  34 #include "memory/metaspaceClosure.hpp"
  35 #include "memory/resourceArea.hpp"
  36 #include "oops/oop.inline.hpp"
  37 #include "runtime/atomic.hpp"
  38 #include "runtime/orderAccess.inline.hpp"
  39 #include "runtime/safepointVerifiers.hpp"
  40 #include "utilities/hashtable.inline.hpp"
  41 
  42 // Optimization: if any dictionary needs resizing, we set this flag,
  43 // so that we dont't have to walk all dictionaries to check if any actually
  44 // needs resizing, which is costly to do at Safepoint.
  45 bool Dictionary::_some_dictionary_needs_resizing = false;
  46 
  47 size_t Dictionary::entry_size() {
  48   if (DumpSharedSpaces) {
  49     return SystemDictionaryShared::dictionary_entry_size();
  50   } else {
  51     return sizeof(DictionaryEntry);
  52   }
  53 }
  54 
  55 Dictionary::Dictionary(ClassLoaderData* loader_data, int table_size, bool resizable)
  56   : _loader_data(loader_data), _resizable(resizable), _needs_resizing(false),
  57   Hashtable<InstanceKlass*, mtClass>(table_size, (int)entry_size()) {
  58 };
  59 
  60 
  61 Dictionary::Dictionary(ClassLoaderData* loader_data,
  62                        int table_size, HashtableBucket<mtClass>* t,
  63                        int number_of_entries, bool resizable)
  64   : _loader_data(loader_data), _resizable(resizable), _needs_resizing(false),
  65   Hashtable<InstanceKlass*, mtClass>(table_size, (int)entry_size(), t, number_of_entries) {
  66 };
  67 
  68 Dictionary::~Dictionary() {
  69   DictionaryEntry* probe = NULL;
  70   for (int index = 0; index < table_size(); index++) {
  71     for (DictionaryEntry** p = bucket_addr(index); *p != NULL; ) {
  72       probe = *p;
  73       *p = probe->next();
  74       free_entry(probe);
  75     }
  76   }
  77   assert(number_of_entries() == 0, "should have removed all entries");
  78   assert(new_entry_free_list() == NULL, "entry present on Dictionary's free list");
  79   free_buckets();
  80 }
  81 
  82 DictionaryEntry* Dictionary::new_entry(unsigned int hash, InstanceKlass* klass) {
  83   DictionaryEntry* entry = (DictionaryEntry*)Hashtable<InstanceKlass*, mtClass>::allocate_new_entry(hash, klass);
  84   entry->set_pd_set(NULL);
  85   assert(klass->is_instance_klass(), "Must be");
  86   if (DumpSharedSpaces) {
  87     SystemDictionaryShared::init_shared_dictionary_entry(klass, entry);
  88   }
  89   return entry;
  90 }
  91 
  92 
  93 void Dictionary::free_entry(DictionaryEntry* entry) {
  94   // avoid recursion when deleting linked list
  95   // pd_set is accessed during a safepoint.
  96   while (entry->pd_set() != NULL) {
  97     ProtectionDomainEntry* to_delete = entry->pd_set();
  98     entry->set_pd_set(to_delete->next());
  99     delete to_delete;
 100   }
 101   // Unlink from the Hashtable prior to freeing
 102   unlink_entry(entry);
 103   FREE_C_HEAP_ARRAY(char, entry);
 104 }
 105 
 106 const int _resize_load_trigger = 5;       // load factor that will trigger the resize
 107 const double _resize_factor    = 2.0;     // by how much we will resize using current number of entries
 108 const int _resize_max_size     = 40423;   // the max dictionary size allowed
 109 const int _primelist[] = {107, 1009, 2017, 4049, 5051, 10103, 20201, _resize_max_size};
 110 const int _prime_array_size = sizeof(_primelist)/sizeof(int);
 111 
 112 // Calculate next "good" dictionary size based on requested count
 113 static int calculate_dictionary_size(int requested) {
 114   int newsize = _primelist[0];
 115   int index = 0;
 116   for (newsize = _primelist[index]; index < (_prime_array_size - 1);
 117        newsize = _primelist[++index]) {
 118     if (requested <= newsize) {
 119       break;
 120     }
 121   }
 122   return newsize;
 123 }
 124 
 125 bool Dictionary::does_any_dictionary_needs_resizing() {
 126   return Dictionary::_some_dictionary_needs_resizing;
 127 }
 128 
 129 void Dictionary::check_if_needs_resize() {
 130   if (_resizable == true) {
 131     if (number_of_entries() > (_resize_load_trigger*table_size())) {
 132       _needs_resizing = true;
 133       Dictionary::_some_dictionary_needs_resizing = true;
 134     }
 135   }
 136 }
 137 
 138 bool Dictionary::resize_if_needed() {
 139   int desired_size = 0;
 140   if (_needs_resizing == true) {
 141     desired_size = calculate_dictionary_size((int)(_resize_factor*number_of_entries()));
 142     if (desired_size >= _resize_max_size) {
 143       desired_size = _resize_max_size;
 144       // We have reached the limit, turn resizing off
 145       _resizable = false;
 146     }
 147     if ((desired_size != 0) && (desired_size != table_size())) {
 148       if (!resize(desired_size)) {
 149         // Something went wrong, turn resizing off
 150         _resizable = false;
 151       }
 152     }
 153   }
 154 
 155   _needs_resizing = false;
 156   Dictionary::_some_dictionary_needs_resizing = false;
 157 
 158   return (desired_size != 0);
 159 }
 160 
 161 bool DictionaryEntry::contains_protection_domain(oop protection_domain) const {
 162 #ifdef ASSERT
 163   if (oopDesc::equals(protection_domain, instance_klass()->protection_domain())) {
 164     // Ensure this doesn't show up in the pd_set (invariant)
 165     bool in_pd_set = false;
 166     for (ProtectionDomainEntry* current = pd_set_acquire();
 167                                 current != NULL;
 168                                 current = current->next()) {
 169       if (oopDesc::equals(current->object_no_keepalive(), protection_domain)) {
 170         in_pd_set = true;
 171         break;
 172       }
 173     }
 174     if (in_pd_set) {
 175       assert(false, "A klass's protection domain should not show up "
 176                     "in its sys. dict. PD set");
 177     }
 178   }
 179 #endif /* ASSERT */
 180 
 181   if (oopDesc::equals(protection_domain, instance_klass()->protection_domain())) {
 182     // Succeeds trivially
 183     return true;
 184   }
 185 
 186   for (ProtectionDomainEntry* current = pd_set_acquire();
 187                               current != NULL;
 188                               current = current->next()) {
 189     if (oopDesc::equals(current->object_no_keepalive(), protection_domain)) return true;
 190   }
 191   return false;
 192 }
 193 
 194 
 195 void DictionaryEntry::add_protection_domain(Dictionary* dict, Handle protection_domain) {
 196   assert_locked_or_safepoint(SystemDictionary_lock);
 197   if (!contains_protection_domain(protection_domain())) {
 198     ProtectionDomainCacheEntry* entry = SystemDictionary::cache_get(protection_domain);
 199     ProtectionDomainEntry* new_head =
 200                 new ProtectionDomainEntry(entry, pd_set());
 201     // Warning: Preserve store ordering.  The SystemDictionary is read
 202     //          without locks.  The new ProtectionDomainEntry must be
 203     //          complete before other threads can be allowed to see it
 204     //          via a store to _pd_set.
 205     release_set_pd_set(new_head);
 206   }
 207   LogTarget(Trace, protectiondomain) lt;
 208   if (lt.is_enabled()) {
 209     LogStream ls(lt);
 210     print_count(&ls);
 211   }
 212 }
 213 
 214 // During class loading we may have cached a protection domain that has
 215 // since been unreferenced, so this entry should be cleared.
 216 void Dictionary::clean_cached_protection_domains(DictionaryEntry* probe) {
 217   assert_locked_or_safepoint(SystemDictionary_lock);
 218 
 219   ProtectionDomainEntry* current = probe->pd_set();
 220   ProtectionDomainEntry* prev = NULL;
 221   while (current != NULL) {
 222     if (current->object_no_keepalive() == NULL) {
 223       LogTarget(Debug, protectiondomain) lt;
 224       if (lt.is_enabled()) {
 225         ResourceMark rm;
 226         // Print out trace information
 227         LogStream ls(lt);
 228         ls.print_cr("PD in set is not alive:");
 229         ls.print("class loader: "); loader_data()->class_loader()->print_value_on(&ls);
 230         ls.print(" loading: "); probe->instance_klass()->print_value_on(&ls);
 231         ls.cr();
 232       }
 233       if (probe->pd_set() == current) {
 234         probe->set_pd_set(current->next());
 235       } else {
 236         assert(prev != NULL, "should be set by alive entry");
 237         prev->set_next(current->next());
 238       }
 239       ProtectionDomainEntry* to_delete = current;
 240       current = current->next();
 241       delete to_delete;
 242     } else {
 243       prev = current;
 244       current = current->next();
 245     }
 246   }
 247 }
 248 
 249 
 250 void Dictionary::do_unloading() {
 251   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
 252 
 253   // The NULL class loader doesn't initiate loading classes from other class loaders
 254   if (loader_data() == ClassLoaderData::the_null_class_loader_data()) {
 255     return;
 256   }
 257 
 258   // Remove unloaded entries and classes from this dictionary
 259   DictionaryEntry* probe = NULL;
 260   for (int index = 0; index < table_size(); index++) {
 261     for (DictionaryEntry** p = bucket_addr(index); *p != NULL; ) {
 262       probe = *p;
 263       InstanceKlass* ik = probe->instance_klass();
 264       ClassLoaderData* k_def_class_loader_data = ik->class_loader_data();
 265 
 266       // If the klass that this loader initiated is dead,
 267       // (determined by checking the defining class loader)
 268       // remove this entry.
 269       if (k_def_class_loader_data->is_unloading()) {
 270         assert(k_def_class_loader_data != loader_data(),
 271                "cannot have live defining loader and unreachable klass");
 272         *p = probe->next();
 273         free_entry(probe);
 274         continue;
 275       }
 276       // Clean pd_set
 277       clean_cached_protection_domains(probe);
 278       p = probe->next_addr();
 279     }
 280   }
 281 }
 282 
 283 void Dictionary::remove_classes_in_error_state() {
 284   assert(DumpSharedSpaces, "supported only when dumping");
 285   DictionaryEntry* probe = NULL;
 286   for (int index = 0; index < table_size(); index++) {
 287     for (DictionaryEntry** p = bucket_addr(index); *p != NULL; ) {
 288       probe = *p;
 289       InstanceKlass* ik = probe->instance_klass();
 290       if (ik->is_in_error_state()) { // purge this entry
 291         *p = probe->next();
 292         free_entry(probe);
 293         ResourceMark rm;
 294         tty->print_cr("Preload Warning: Removed error class: %s", ik->external_name());
 295         continue;
 296       }
 297 
 298       p = probe->next_addr();
 299     }
 300   }
 301 }
 302 
 303 //   Just the classes from defining class loaders
 304 void Dictionary::classes_do(void f(InstanceKlass*)) {
 305   for (int index = 0; index < table_size(); index++) {
 306     for (DictionaryEntry* probe = bucket(index);
 307                           probe != NULL;
 308                           probe = probe->next()) {
 309       InstanceKlass* k = probe->instance_klass();
 310       if (loader_data() == k->class_loader_data()) {
 311         f(k);
 312       }
 313     }
 314   }
 315 }
 316 
 317 // Added for initialize_itable_for_klass to handle exceptions
 318 //   Just the classes from defining class loaders
 319 void Dictionary::classes_do(void f(InstanceKlass*, TRAPS), TRAPS) {
 320   for (int index = 0; index < table_size(); index++) {
 321     for (DictionaryEntry* probe = bucket(index);
 322                           probe != NULL;
 323                           probe = probe->next()) {
 324       InstanceKlass* k = probe->instance_klass();
 325       if (loader_data() == k->class_loader_data()) {
 326         f(k, CHECK);
 327       }
 328     }
 329   }
 330 }
 331 
 332 // All classes, and their class loaders, including initiating class loaders
 333 void Dictionary::all_entries_do(void f(InstanceKlass*, ClassLoaderData*)) {
 334   for (int index = 0; index < table_size(); index++) {
 335     for (DictionaryEntry* probe = bucket(index);
 336                           probe != NULL;
 337                           probe = probe->next()) {
 338       InstanceKlass* k = probe->instance_klass();
 339       f(k, loader_data());
 340     }
 341   }
 342 }
 343 
 344 // Used to scan and relocate the classes during CDS archive dump.
 345 void Dictionary::classes_do(MetaspaceClosure* it) {
 346   assert(DumpSharedSpaces, "dump-time only");
 347   for (int index = 0; index < table_size(); index++) {
 348     for (DictionaryEntry* probe = bucket(index);
 349                           probe != NULL;
 350                           probe = probe->next()) {
 351       it->push(probe->klass_addr());
 352       ((SharedDictionaryEntry*)probe)->metaspace_pointers_do(it);
 353     }
 354   }
 355 }
 356 
 357 
 358 
 359 // Add a loaded class to the dictionary.
 360 // Readers of the SystemDictionary aren't always locked, so _buckets
 361 // is volatile. The store of the next field in the constructor is
 362 // also cast to volatile;  we do this to ensure store order is maintained
 363 // by the compilers.
 364 
 365 void Dictionary::add_klass(unsigned int hash, Symbol* class_name,
 366                            InstanceKlass* obj) {
 367   assert_locked_or_safepoint(SystemDictionary_lock);
 368   assert(obj != NULL, "adding NULL obj");
 369   assert(obj->name() == class_name, "sanity check on name");
 370 
 371   DictionaryEntry* entry = new_entry(hash, obj);
 372   int index = hash_to_index(hash);
 373   add_entry(index, entry);
 374   check_if_needs_resize();
 375 }
 376 
 377 
 378 // This routine does not lock the dictionary.
 379 //
 380 // Since readers don't hold a lock, we must make sure that system
 381 // dictionary entries are only removed at a safepoint (when only one
 382 // thread is running), and are added to in a safe way (all links must
 383 // be updated in an MT-safe manner).
 384 //
 385 // Callers should be aware that an entry could be added just after
 386 // _buckets[index] is read here, so the caller will not see the new entry.
 387 DictionaryEntry* Dictionary::get_entry(int index, unsigned int hash,
 388                                        Symbol* class_name) {
 389   for (DictionaryEntry* entry = bucket(index);
 390                         entry != NULL;
 391                         entry = entry->next()) {
 392     if (entry->hash() == hash && entry->equals(class_name)) {
 393       if (!DumpSharedSpaces || SystemDictionaryShared::is_builtin(entry)) {
 394         return entry;
 395       }
 396     }
 397   }
 398   return NULL;
 399 }
 400 
 401 
 402 InstanceKlass* Dictionary::find(unsigned int hash, Symbol* name,
 403                                 Handle protection_domain) {
 404   NoSafepointVerifier nsv;
 405 
 406   int index = hash_to_index(hash);
 407   DictionaryEntry* entry = get_entry(index, hash, name);
 408   if (entry != NULL && entry->is_valid_protection_domain(protection_domain)) {
 409     return entry->instance_klass();
 410   } else {
 411     return NULL;
 412   }
 413 }
 414 
 415 
 416 InstanceKlass* Dictionary::find_class(int index, unsigned int hash,
 417                                       Symbol* name) {
 418   assert_locked_or_safepoint(SystemDictionary_lock);
 419   assert (index == index_for(name), "incorrect index?");
 420 
 421   DictionaryEntry* entry = get_entry(index, hash, name);
 422   return (entry != NULL) ? entry->instance_klass() : NULL;
 423 }
 424 
 425 
 426 // Variant of find_class for shared classes.  No locking required, as
 427 // that table is static.
 428 
 429 InstanceKlass* Dictionary::find_shared_class(int index, unsigned int hash,
 430                                              Symbol* name) {
 431   assert (index == index_for(name), "incorrect index?");
 432 
 433   DictionaryEntry* entry = get_entry(index, hash, name);
 434   return (entry != NULL) ? entry->instance_klass() : NULL;
 435 }
 436 
 437 
 438 void Dictionary::add_protection_domain(int index, unsigned int hash,
 439                                        InstanceKlass* klass,
 440                                        Handle protection_domain,
 441                                        TRAPS) {
 442   Symbol*  klass_name = klass->name();
 443   DictionaryEntry* entry = get_entry(index, hash, klass_name);
 444 
 445   assert(entry != NULL,"entry must be present, we just created it");
 446   assert(protection_domain() != NULL,
 447          "real protection domain should be present");
 448 
 449   entry->add_protection_domain(this, protection_domain);
 450 
 451 #ifdef ASSERT
 452   assert(loader_data() != ClassLoaderData::the_null_class_loader_data(), "doesn't make sense");
 453 #endif
 454 
 455   assert(entry->contains_protection_domain(protection_domain()),
 456          "now protection domain should be present");
 457 }
 458 
 459 
 460 bool Dictionary::is_valid_protection_domain(unsigned int hash,
 461                                             Symbol* name,
 462                                             Handle protection_domain) {
 463   int index = hash_to_index(hash);
 464   DictionaryEntry* entry = get_entry(index, hash, name);
 465   return entry->is_valid_protection_domain(protection_domain);
 466 }
 467 
 468 #if INCLUDE_CDS
 469 static bool is_jfr_event_class(Klass *k) {
 470   while (k) {
 471     if (k->name()->equals("jdk/jfr/Event")) {
 472       return true;
 473     }
 474     k = k->super();
 475   }
 476   return false;
 477 }
 478 
 479 void Dictionary::reorder_dictionary_for_sharing() {
 480 
 481   // Copy all the dictionary entries into a single master list.
 482   assert(DumpSharedSpaces, "Should only be used at dump time");
 483 
 484   DictionaryEntry* master_list = NULL;
 485   for (int i = 0; i < table_size(); ++i) {
 486     DictionaryEntry* p = bucket(i);
 487     while (p != NULL) {
 488       DictionaryEntry* next = p->next();
 489       InstanceKlass*ik = p->instance_klass();
 490       if (ik->has_signer_and_not_archived()) {
 491         // We cannot include signed classes in the archive because the certificates
 492         // used during dump time may be different than those used during
 493         // runtime (due to expiration, etc).
 494         ResourceMark rm;
 495         tty->print_cr("Preload Warning: Skipping %s from signed JAR",
 496                        ik->name()->as_C_string());
 497         free_entry(p);
 498       } else if (is_jfr_event_class(ik)) {
 499         // We cannot include JFR event classes because they need runtime-specific
 500         // instrumentation in order to work with -XX:FlightRecorderOptions=retransform=false.
 501         // There are only a small number of these classes, so it's not worthwhile to
 502         // support them and make CDS more complicated.
 503         ResourceMark rm;
 504         tty->print_cr("Skipping JFR event class %s", ik->name()->as_C_string());
 505         free_entry(p);
 506       } else {
 507         p->set_next(master_list);
 508         master_list = p;
 509       }
 510       p = next;
 511     }
 512     set_entry(i, NULL);
 513   }
 514 
 515   // Add the dictionary entries back to the list in the correct buckets.
 516   while (master_list != NULL) {
 517     DictionaryEntry* p = master_list;
 518     master_list = master_list->next();
 519     p->set_next(NULL);
 520     Symbol* class_name = p->instance_klass()->name();
 521     // Since the null class loader data isn't copied to the CDS archive,
 522     // compute the hash with NULL for loader data.
 523     unsigned int hash = compute_hash(class_name);
 524     int index = hash_to_index(hash);
 525     p->set_hash(hash);
 526     p->set_next(bucket(index));
 527     set_entry(index, p);
 528   }
 529 }
 530 #endif
 531 
 532 SymbolPropertyTable::SymbolPropertyTable(int table_size)
 533   : Hashtable<Symbol*, mtSymbol>(table_size, sizeof(SymbolPropertyEntry))
 534 {
 535 }
 536 SymbolPropertyTable::SymbolPropertyTable(int table_size, HashtableBucket<mtSymbol>* t,
 537                                          int number_of_entries)
 538   : Hashtable<Symbol*, mtSymbol>(table_size, sizeof(SymbolPropertyEntry), t, number_of_entries)
 539 {
 540 }
 541 
 542 
 543 SymbolPropertyEntry* SymbolPropertyTable::find_entry(int index, unsigned int hash,
 544                                                      Symbol* sym,
 545                                                      intptr_t sym_mode) {
 546   assert(index == index_for(sym, sym_mode), "incorrect index?");
 547   for (SymbolPropertyEntry* p = bucket(index); p != NULL; p = p->next()) {
 548     if (p->hash() == hash && p->symbol() == sym && p->symbol_mode() == sym_mode) {
 549       return p;
 550     }
 551   }
 552   return NULL;
 553 }
 554 
 555 
 556 SymbolPropertyEntry* SymbolPropertyTable::add_entry(int index, unsigned int hash,
 557                                                     Symbol* sym, intptr_t sym_mode) {
 558   assert_locked_or_safepoint(SystemDictionary_lock);
 559   assert(index == index_for(sym, sym_mode), "incorrect index?");
 560   assert(find_entry(index, hash, sym, sym_mode) == NULL, "no double entry");
 561 
 562   SymbolPropertyEntry* p = new_entry(hash, sym, sym_mode);
 563   Hashtable<Symbol*, mtSymbol>::add_entry(index, p);
 564   return p;
 565 }
 566 
 567 void SymbolPropertyTable::oops_do(OopClosure* f) {
 568   for (int index = 0; index < table_size(); index++) {
 569     for (SymbolPropertyEntry* p = bucket(index); p != NULL; p = p->next()) {
 570       if (p->method_type() != NULL) {
 571         f->do_oop(p->method_type_addr());
 572       }
 573     }
 574   }
 575 }
 576 
 577 void SymbolPropertyTable::methods_do(void f(Method*)) {
 578   for (int index = 0; index < table_size(); index++) {
 579     for (SymbolPropertyEntry* p = bucket(index); p != NULL; p = p->next()) {
 580       Method* prop = p->method();
 581       if (prop != NULL) {
 582         f((Method*)prop);
 583       }
 584     }
 585   }
 586 }
 587 
 588 
 589 // ----------------------------------------------------------------------------
 590 
 591 void Dictionary::print_on(outputStream* st) const {
 592   ResourceMark rm;
 593 
 594   assert(loader_data() != NULL, "loader data should not be null");
 595   st->print_cr("Java dictionary (table_size=%d, classes=%d)",
 596                table_size(), number_of_entries());
 597   st->print_cr("^ indicates that initiating loader is different from defining loader");
 598 
 599   for (int index = 0; index < table_size(); index++) {
 600     for (DictionaryEntry* probe = bucket(index);
 601                           probe != NULL;
 602                           probe = probe->next()) {
 603       Klass* e = probe->instance_klass();
 604       bool is_defining_class =
 605          (loader_data() == e->class_loader_data());
 606       st->print("%4d: %s%s", index, is_defining_class ? " " : "^", e->external_name());
 607       ClassLoaderData* cld = e->class_loader_data();
 608       if (cld == NULL) {
 609         // Shared class not restored yet in shared dictionary
 610         st->print(", loader data <shared, not restored>");
 611       } else if (!loader_data()->is_the_null_class_loader_data()) {
 612         // Class loader output for the dictionary for the null class loader data is
 613         // redundant and obvious.
 614         st->print(", ");
 615         cld->print_value_on(st);
 616       }
 617       st->cr();
 618     }
 619   }
 620   tty->cr();
 621 }
 622 
 623 void DictionaryEntry::verify() {
 624   Klass* e = instance_klass();
 625   guarantee(e->is_instance_klass(),
 626                           "Verify of dictionary failed");
 627   e->verify();
 628   verify_protection_domain_set();
 629 }
 630 
 631 void Dictionary::verify() {
 632   guarantee(number_of_entries() >= 0, "Verify of dictionary failed");
 633 
 634   ClassLoaderData* cld = loader_data();
 635   // class loader must be present;  a null class loader is the
 636   // boostrap loader
 637   guarantee(cld != NULL || DumpSharedSpaces ||
 638             cld->class_loader() == NULL ||
 639             cld->class_loader()->is_instance(),
 640             "checking type of class_loader");
 641 
 642   ResourceMark rm;
 643   stringStream tempst;
 644   tempst.print("System Dictionary for %s", cld->loader_name());
 645   verify_table<DictionaryEntry>(tempst.as_string());
 646 }