classLoaderData.cpp revision 3602:da91efe96a93
1/* 2 * Copyright (c) 2012, 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// A ClassLoaderData identifies the full set of class types that a class 26// loader's name resolution strategy produces for a given configuration of the 27// class loader. 28// Class types in the ClassLoaderData may be defined by from class file binaries 29// provided by the class loader, or from other class loader it interacts with 30// according to its name resolution strategy. 31// 32// Class loaders that implement a deterministic name resolution strategy 33// (including with respect to their delegation behavior), such as the boot, the 34// extension, and the system loaders of the JDK's built-in class loader 35// hierarchy, always produce the same linkset for a given configuration. 36// 37// ClassLoaderData carries information related to a linkset (e.g., 38// metaspace holding its klass definitions). 39// The System Dictionary and related data structures (e.g., placeholder table, 40// loader constraints table) as well as the runtime representation of classes 41// only reference ClassLoaderData. 42// 43// Instances of java.lang.ClassLoader holds a pointer to a ClassLoaderData that 44// that represent the loader's "linking domain" in the JVM. 45// 46// The bootstrap loader (represented by NULL) also has a ClassLoaderData, 47// the singleton class the_null_class_loader_data(). 48 49#include "precompiled.hpp" 50#include "classfile/classLoaderData.hpp" 51#include "classfile/classLoaderData.inline.hpp" 52#include "classfile/javaClasses.hpp" 53#include "classfile/systemDictionary.hpp" 54#include "code/codeCache.hpp" 55#include "memory/metadataFactory.hpp" 56#include "memory/metaspaceShared.hpp" 57#include "prims/jvmtiRedefineClasses.hpp" 58#include "runtime/jniHandles.hpp" 59#include "runtime/mutex.hpp" 60#include "runtime/safepoint.hpp" 61#include "runtime/synchronizer.hpp" 62#include "utilities/growableArray.hpp" 63#include "utilities/ostream.hpp" 64 65ClassLoaderData * ClassLoaderData::_the_null_class_loader_data = NULL; 66 67ClassLoaderData::ClassLoaderData(Handle h_class_loader) : _class_loader(h_class_loader()), 68 _metaspace(NULL), _unloading(false), _klasses(NULL), 69 _claimed(0), _jmethod_ids(NULL), _handles(NULL), 70 _deallocate_list(NULL), _next(NULL), 71 _metaspace_lock(new Mutex(Monitor::leaf+1, "Metaspace allocation lock", true)) { 72 // empty 73} 74 75bool ClassLoaderData::claim() { 76 if (_claimed == 1) { 77 return false; 78 } 79 80 return (int) Atomic::cmpxchg(1, &_claimed, 0) == 0; 81} 82 83void ClassLoaderData::oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim) { 84 if (must_claim && !claim()) { 85 return; 86 } 87 88 f->do_oop(&_class_loader); 89 _handles->oops_do(f); 90 if (klass_closure != NULL) { 91 classes_do(klass_closure); 92 } 93} 94 95void ClassLoaderData::classes_do(KlassClosure* klass_closure) { 96 for (Klass* k = _klasses; k != NULL; k = k->next_link()) { 97 klass_closure->do_klass(k); 98 } 99} 100 101void ClassLoaderData::classes_do(void f(InstanceKlass*)) { 102 for (Klass* k = _klasses; k != NULL; k = k->next_link()) { 103 if (k->oop_is_instance()) { 104 f(InstanceKlass::cast(k)); 105 } 106 } 107} 108 109void ClassLoaderData::record_dependency(Klass* k, TRAPS) { 110 ClassLoaderData * const from_cld = this; 111 ClassLoaderData * const to_cld = k->class_loader_data(); 112 113 // Records dependency between non-null class loaders only. 114 if (to_cld->is_the_null_class_loader_data() || from_cld->is_the_null_class_loader_data()) { 115 return; 116 } 117 118 // Check that this dependency isn't from the same or parent class_loader 119 oop to = to_cld->class_loader(); 120 oop from = from_cld->class_loader(); 121 122 oop curr = from; 123 while (curr != NULL) { 124 if (curr == to) { 125 return; // this class loader is in the parent list, no need to add it. 126 } 127 curr = java_lang_ClassLoader::parent(curr); 128 } 129 130 // It's a dependency we won't find through GC, add it. This is relatively rare 131 from_cld->add_dependency(to_cld, CHECK); 132} 133 134bool ClassLoaderData::has_dependency(ClassLoaderData* dependency) { 135 oop loader = dependency->class_loader(); 136 137 // Get objArrayOop out of the class_loader oop and see if this dependency 138 // is there. Don't safepoint! These are all oops. 139 // Dependency list is (oop class_loader, objArrayOop next) 140 objArrayOop ok = (objArrayOop)java_lang_ClassLoader::dependencies(class_loader()); 141 while (ok != NULL) { 142 if (ok->obj_at(0) == loader) { 143 return true; 144 } 145 ok = (objArrayOop)ok->obj_at(1); 146 } 147 return false; 148} 149 150void ClassLoaderData::add_dependency(ClassLoaderData* dependency, TRAPS) { 151 // Minimize the number of duplicates in the list. 152 if (has_dependency(dependency)) { 153 return; 154 } 155 156 // Create a new dependency node with fields for (class_loader, next) 157 objArrayOop deps = oopFactory::new_objectArray(2, CHECK); 158 deps->obj_at_put(0, dependency->class_loader()); 159 160 // Add this lock free, using compare and exchange, need barriers for GC 161 // Do the barrier first. 162 HeapWord* addr = java_lang_ClassLoader::dependencies_addr(class_loader()); 163 while (true) { 164 oop old_dependency = java_lang_ClassLoader::dependencies(class_loader()); 165 deps->obj_at_put(1, old_dependency); 166 167 oop newold = oopDesc::atomic_compare_exchange_oop((oop)deps, addr, old_dependency, true); 168 if (newold == old_dependency) { 169 update_barrier_set((void*)addr, (oop)deps); 170 // we won the race to add this dependency 171 break; 172 } 173 } 174} 175 176 177void ClassLoaderDataGraph::clear_claimed_marks() { 178 for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) { 179 cld->clear_claimed(); 180 } 181} 182 183void ClassLoaderData::add_class(Klass* k) { 184 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag); 185 Klass* old_value = _klasses; 186 k->set_next_link(old_value); 187 // link the new item into the list 188 _klasses = k; 189 190 if (TraceClassLoaderData && k->class_loader_data() != NULL) { 191 ResourceMark rm; 192 tty->print_cr("[TraceClassLoaderData] Adding k: " PTR_FORMAT " %s to CLD: " 193 PTR_FORMAT " loader: " PTR_FORMAT " %s", 194 k, 195 k->external_name(), 196 k->class_loader_data(), 197 k->class_loader(), 198 k->class_loader() != NULL ? k->class_loader()->klass()->external_name() : "NULL" 199 ); 200 } 201} 202 203// This is called by InstanceKlass::deallocate_contents() to remove the 204// scratch_class for redefine classes. We need a lock because there it may not 205// be called at a safepoint if there's an error. 206void ClassLoaderData::remove_class(Klass* scratch_class) { 207 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag); 208 Klass* prev = NULL; 209 for (Klass* k = _klasses; k != NULL; k = k->next_link()) { 210 if (k == scratch_class) { 211 if (prev == NULL) { 212 _klasses = k->next_link(); 213 } else { 214 Klass* next = k->next_link(); 215 prev->set_next_link(next); 216 } 217 return; 218 } 219 prev = k; 220 } 221 ShouldNotReachHere(); // should have found this class!! 222} 223 224ClassLoaderData::~ClassLoaderData() { 225 Metaspace *m = _metaspace; 226 if (m != NULL) { 227 _metaspace = NULL; 228 // release the metaspace 229 delete m; 230 // release the handles 231 if (_handles != NULL) { 232 JNIHandleBlock::release_block(_handles); 233 _handles = NULL; 234 } 235 } 236 237 // Clear all the JNI handles for methods 238 // These aren't deallocated and are going to look like a leak, but that's 239 // needed because we can't really get rid of jmethodIDs because we don't 240 // know when native code is going to stop using them. The spec says that 241 // they're "invalid" but existing programs likely rely on their being 242 // NULL after class unloading. 243 if (_jmethod_ids != NULL) { 244 Method::clear_jmethod_ids(this); 245 } 246 // Delete lock 247 delete _metaspace_lock; 248 249 // Delete free list 250 if (_deallocate_list != NULL) { 251 delete _deallocate_list; 252 } 253} 254 255Metaspace* ClassLoaderData::metaspace_non_null() { 256 // If the metaspace has not been allocated, create a new one. Might want 257 // to create smaller arena for Reflection class loaders also. 258 // The reason for the delayed allocation is because some class loaders are 259 // simply for delegating with no metadata of their own. 260 if (_metaspace == NULL) { 261 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag); 262 // Check again if metaspace has been allocated while we were getting this lock. 263 if (_metaspace != NULL) { 264 return _metaspace; 265 } 266 if (class_loader() == NULL) { 267 assert(this == the_null_class_loader_data(), "Must be"); 268 size_t word_size = Metaspace::first_chunk_word_size(); 269 set_metaspace(new Metaspace(_metaspace_lock, word_size)); 270 } else { 271 set_metaspace(new Metaspace(_metaspace_lock)); // default size for now. 272 } 273 } 274 return _metaspace; 275} 276 277JNIHandleBlock* ClassLoaderData::handles() const { return _handles; } 278void ClassLoaderData::set_handles(JNIHandleBlock* handles) { _handles = handles; } 279 280jobject ClassLoaderData::add_handle(Handle h) { 281 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag); 282 if (handles() == NULL) { 283 set_handles(JNIHandleBlock::allocate_block()); 284 } 285 return handles()->allocate_handle(h()); 286} 287 288// Add this metadata pointer to be freed when it's safe. This is only during 289// class unloading because Handles might point to this metadata field. 290void ClassLoaderData::add_to_deallocate_list(Metadata* m) { 291 // Metadata in shared region isn't deleted. 292 if (!m->is_shared()) { 293 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag); 294 if (_deallocate_list == NULL) { 295 _deallocate_list = new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(100, true); 296 } 297 _deallocate_list->append_if_missing(m); 298 } 299} 300 301// Deallocate free metadata on the free list. How useful the PermGen was! 302void ClassLoaderData::free_deallocate_list() { 303 // Don't need lock, at safepoint 304 assert(SafepointSynchronize::is_at_safepoint(), "only called at safepoint"); 305 if (_deallocate_list == NULL) { 306 return; 307 } 308 // Go backwards because this removes entries that are freed. 309 for (int i = _deallocate_list->length() - 1; i >= 0; i--) { 310 Metadata* m = _deallocate_list->at(i); 311 if (!m->on_stack()) { 312 _deallocate_list->remove_at(i); 313 // There are only three types of metadata that we deallocate directly. 314 // Cast them so they can be used by the template function. 315 if (m->is_method()) { 316 MetadataFactory::free_metadata(this, (Method*)m); 317 } else if (m->is_constantPool()) { 318 MetadataFactory::free_metadata(this, (ConstantPool*)m); 319 } else if (m->is_klass()) { 320 MetadataFactory::free_metadata(this, (InstanceKlass*)m); 321 } else { 322 ShouldNotReachHere(); 323 } 324 } 325 } 326} 327 328#ifndef PRODUCT 329void ClassLoaderData::print_loader(ClassLoaderData *loader_data, outputStream* out) { 330 oop class_loader = loader_data->class_loader(); 331 out->print("%s", SystemDictionary::loader_name(class_loader)); 332} 333 334// Define to dump klasses 335#undef CLD_DUMP_KLASSES 336 337void ClassLoaderData::dump(outputStream * const out) { 338 ResourceMark rm; 339 out->print("ClassLoaderData CLD: "PTR_FORMAT", loader: "PTR_FORMAT", loader_klass: "PTR_FORMAT" %s {", 340 this, class_loader(), 341 class_loader() != NULL ? class_loader()->klass() : NULL, 342 class_loader() != NULL ? class_loader()->klass()->external_name() : "NULL"); 343 if (claimed()) out->print(" claimed "); 344 if (is_unloading()) out->print(" unloading "); 345 out->print(" handles " INTPTR_FORMAT, handles()); 346 out->cr(); 347 if (metaspace_or_null() != NULL) { 348 out->print_cr("metaspace: " PTR_FORMAT, metaspace_or_null()); 349 metaspace_or_null()->dump(out); 350 } else { 351 out->print_cr("metaspace: NULL"); 352 } 353 354#ifdef CLD_DUMP_KLASSES 355 if (Verbose) { 356 ResourceMark rm; 357 Klass* k = _klasses; 358 while (k != NULL) { 359 out->print_cr("klass "PTR_FORMAT", %s, CT: %d, MUT: %d", k, k->name()->as_C_string(), 360 k->has_modified_oops(), k->has_accumulated_modified_oops()); 361 k = k->next_link(); 362 } 363 } 364#endif // CLD_DUMP_KLASSES 365#undef CLD_DUMP_KLASSES 366 if (_jmethod_ids != NULL) { 367 Method::print_jmethod_ids(this, out); 368 } 369 out->print_cr("}"); 370} 371#endif // PRODUCT 372 373void ClassLoaderData::verify() { 374 oop cl = class_loader(); 375 376 guarantee(this == class_loader_data(cl), "Must be the same"); 377 guarantee(cl != NULL || this == ClassLoaderData::the_null_class_loader_data(), "must be"); 378 379 // Verify the integrity of the allocated space. 380 if (metaspace_or_null() != NULL) { 381 metaspace_or_null()->verify(); 382 } 383 384 for (Klass* k = _klasses; k != NULL; k = k->next_link()) { 385 guarantee(k->class_loader_data() == this, "Must be the same"); 386 k->verify(); 387 } 388} 389 390// GC root of class loader data created. 391ClassLoaderData* ClassLoaderDataGraph::_head = NULL; 392ClassLoaderData* ClassLoaderDataGraph::_unloading = NULL; 393ClassLoaderData* ClassLoaderDataGraph::_saved_head = NULL; 394 395 396// Add a new class loader data node to the list. Assign the newly created 397// ClassLoaderData into the java/lang/ClassLoader object as a hidden field 398ClassLoaderData* ClassLoaderDataGraph::add(ClassLoaderData** cld_addr, Handle loader_data) { 399 // Not assigned a class loader data yet. 400 // Create one. 401 ClassLoaderData* *list_head = &_head; 402 ClassLoaderData* next = _head; 403 ClassLoaderData* cld = new ClassLoaderData(loader_data); 404 405 // First, Atomically set it. 406 ClassLoaderData* old = (ClassLoaderData*) Atomic::cmpxchg_ptr(cld, cld_addr, NULL); 407 if (old != NULL) { 408 delete cld; 409 // Returns the data. 410 return old; 411 } 412 413 // We won the race, and therefore the task of adding the data to the list of 414 // class loader data 415 do { 416 cld->set_next(next); 417 ClassLoaderData* exchanged = (ClassLoaderData*)Atomic::cmpxchg_ptr(cld, list_head, next); 418 if (exchanged == next) { 419 if (TraceClassLoaderData) { 420 tty->print("[ClassLoaderData: "); 421 tty->print("create class loader data "PTR_FORMAT, cld); 422 tty->print(" for instance "PTR_FORMAT" of ", cld->class_loader()); 423 loader_data->klass()->name()->print_symbol_on(tty); 424 tty->print_cr("]"); 425 } 426 return cld; 427 } 428 next = exchanged; 429 } while (true); 430} 431 432void ClassLoaderDataGraph::oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim) { 433 for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) { 434 cld->oops_do(f, klass_closure, must_claim); 435 } 436} 437 438void ClassLoaderDataGraph::always_strong_oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim) { 439 if (ClassUnloading) { 440 ClassLoaderData::the_null_class_loader_data()->oops_do(f, klass_closure, must_claim); 441 } else { 442 ClassLoaderDataGraph::oops_do(f, klass_closure, must_claim); 443 } 444} 445 446void ClassLoaderDataGraph::classes_do(KlassClosure* klass_closure) { 447 for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) { 448 cld->classes_do(klass_closure); 449 } 450} 451 452GrowableArray<ClassLoaderData*>* ClassLoaderDataGraph::new_clds() { 453 assert(_head == NULL || _saved_head != NULL, "remember_new_clds(true) not called?"); 454 455 GrowableArray<ClassLoaderData*>* array = new GrowableArray<ClassLoaderData*>(); 456 457 // The CLDs in [_head, _saved_head] were all added during last call to remember_new_clds(true); 458 ClassLoaderData* curr = _head; 459 while (curr != _saved_head) { 460 if (!curr->claimed()) { 461 array->push(curr); 462 463 if (TraceClassLoaderData) { 464 tty->print("[ClassLoaderData] found new CLD: "); 465 curr->print_value_on(tty); 466 tty->cr(); 467 } 468 } 469 470 curr = curr->_next; 471 } 472 473 return array; 474} 475 476#ifndef PRODUCT 477// for debugging and hsfind(x) 478bool ClassLoaderDataGraph::contains(address x) { 479 // I think we need the _metaspace_lock taken here because the class loader 480 // data graph could be changing while we are walking it (new entries added, 481 // new entries being unloaded, etc). 482 if (DumpSharedSpaces) { 483 // There are only two metaspaces to worry about. 484 ClassLoaderData* ncld = ClassLoaderData::the_null_class_loader_data(); 485 return (ncld->ro_metaspace()->contains(x) || ncld->rw_metaspace()->contains(x)); 486 } 487 488 if (UseSharedSpaces && MetaspaceShared::is_in_shared_space(x)) { 489 return true; 490 } 491 492 for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) { 493 if (cld->metaspace_or_null() != NULL && cld->metaspace_or_null()->contains(x)) { 494 return true; 495 } 496 } 497 498 // Could also be on an unloading list which is okay, ie. still allocated 499 // for a little while. 500 for (ClassLoaderData* ucld = _unloading; ucld != NULL; ucld = ucld->next()) { 501 if (ucld->metaspace_or_null() != NULL && ucld->metaspace_or_null()->contains(x)) { 502 return true; 503 } 504 } 505 return false; 506} 507 508bool ClassLoaderDataGraph::contains_loader_data(ClassLoaderData* loader_data) { 509 for (ClassLoaderData* data = _head; data != NULL; data = data->next()) { 510 if (loader_data == data) { 511 return true; 512 } 513 } 514 515 return false; 516} 517#endif // PRODUCT 518 519// Move class loader data from main list to the unloaded list for unloading 520// and deallocation later. 521bool ClassLoaderDataGraph::do_unloading(BoolObjectClosure* is_alive) { 522 ClassLoaderData* data = _head; 523 ClassLoaderData* prev = NULL; 524 bool seen_dead_loader = false; 525 // mark metadata seen on the stack and code cache so we can delete 526 // unneeded entries. 527 bool has_redefined_a_class = JvmtiExport::has_redefined_a_class(); 528 MetadataOnStackMark md_on_stack; 529 while (data != NULL) { 530 if (data->class_loader() == NULL || is_alive->do_object_b(data->class_loader())) { 531 assert(data->claimed(), "class loader data must have been claimed"); 532 if (has_redefined_a_class) { 533 data->classes_do(InstanceKlass::purge_previous_versions); 534 } 535 data->free_deallocate_list(); 536 prev = data; 537 data = data->next(); 538 continue; 539 } 540 seen_dead_loader = true; 541 ClassLoaderData* dead = data; 542 dead->mark_for_unload(); 543 if (TraceClassLoaderData) { 544 tty->print("[ClassLoaderData: unload loader data "PTR_FORMAT, dead); 545 tty->print(" for instance "PTR_FORMAT" of ", dead->class_loader()); 546 dead->class_loader()->klass()->name()->print_symbol_on(tty); 547 tty->print_cr("]"); 548 } 549 data = data->next(); 550 // Remove from loader list. 551 if (prev != NULL) { 552 prev->set_next(data); 553 } else { 554 assert(dead == _head, "sanity check"); 555 _head = data; 556 } 557 dead->set_next(_unloading); 558 _unloading = dead; 559 } 560 return seen_dead_loader; 561} 562 563void ClassLoaderDataGraph::purge() { 564 ClassLoaderData* list = _unloading; 565 _unloading = NULL; 566 ClassLoaderData* next = list; 567 while (next != NULL) { 568 ClassLoaderData* purge_me = next; 569 next = purge_me->next(); 570 delete purge_me; 571 } 572} 573 574// CDS support 575 576// Global metaspaces for writing information to the shared archive. When 577// application CDS is supported, we may need one per metaspace, so this 578// sort of looks like it. 579Metaspace* ClassLoaderData::_ro_metaspace = NULL; 580Metaspace* ClassLoaderData::_rw_metaspace = NULL; 581static bool _shared_metaspaces_initialized = false; 582 583// Initialize shared metaspaces (change to call from somewhere not lazily) 584void ClassLoaderData::initialize_shared_metaspaces() { 585 assert(DumpSharedSpaces, "only use this for dumping shared spaces"); 586 assert(this == ClassLoaderData::the_null_class_loader_data(), 587 "only supported for null loader data for now"); 588 assert (!_shared_metaspaces_initialized, "only initialize once"); 589 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag); 590 _ro_metaspace = new Metaspace(_metaspace_lock, SharedReadOnlySize/wordSize); 591 _rw_metaspace = new Metaspace(_metaspace_lock, SharedReadWriteSize/wordSize); 592 _shared_metaspaces_initialized = true; 593} 594 595Metaspace* ClassLoaderData::ro_metaspace() { 596 assert(_ro_metaspace != NULL, "should already be initialized"); 597 return _ro_metaspace; 598} 599 600Metaspace* ClassLoaderData::rw_metaspace() { 601 assert(_rw_metaspace != NULL, "should already be initialized"); 602 return _rw_metaspace; 603} 604 605 606ClassLoaderDataGraphMetaspaceIterator::ClassLoaderDataGraphMetaspaceIterator() { 607 _data = ClassLoaderDataGraph::_head; 608} 609 610ClassLoaderDataGraphMetaspaceIterator::~ClassLoaderDataGraphMetaspaceIterator() {} 611 612#ifndef PRODUCT 613// callable from debugger 614extern "C" int print_loader_data_graph() { 615 ClassLoaderDataGraph::dump_on(tty); 616 return 0; 617} 618 619void ClassLoaderDataGraph::verify() { 620 for (ClassLoaderData* data = _head; data != NULL; data = data->next()) { 621 data->verify(); 622 } 623} 624 625void ClassLoaderDataGraph::dump_on(outputStream * const out) { 626 for (ClassLoaderData* data = _head; data != NULL; data = data->next()) { 627 data->dump(out); 628 } 629 MetaspaceAux::dump(out); 630} 631 632void ClassLoaderData::print_value_on(outputStream* out) const { 633 if (class_loader() == NULL) { 634 out->print_cr("NULL class_loader"); 635 } else { 636 out->print("class loader "PTR_FORMAT, this); 637 class_loader()->print_value_on(out); 638 } 639} 640#endif // PRODUCT 641