1 /*
   2  * Copyright (c) 2000, 2015, 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.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package java.util.logging;
  27 import java.time.Instant;
  28 import java.util.*;
  29 import java.util.concurrent.atomic.AtomicInteger;
  30 import java.util.concurrent.atomic.AtomicLong;
  31 import java.io.*;
  32 import java.security.AccessController;
  33 import java.security.PrivilegedAction;
  34 import java.time.Clock;
  35 import java.util.function.Predicate;
  36 
  37 import static jdk.internal.logger.SimpleConsoleLogger.isFilteredFrame;
  38 
  39 /**
  40  * LogRecord objects are used to pass logging requests between
  41  * the logging framework and individual log Handlers.
  42  * <p>
  43  * When a LogRecord is passed into the logging framework it
  44  * logically belongs to the framework and should no longer be
  45  * used or updated by the client application.
  46  * <p>
  47  * Note that if the client application has not specified an
  48  * explicit source method name and source class name, then the
  49  * LogRecord class will infer them automatically when they are
  50  * first accessed (due to a call on getSourceMethodName or
  51  * getSourceClassName) by analyzing the call stack.  Therefore,
  52  * if a logging Handler wants to pass off a LogRecord to another
  53  * thread, or to transmit it over RMI, and if it wishes to subsequently
  54  * obtain method name or class name information it should call
  55  * one of getSourceClassName or getSourceMethodName to force
  56  * the values to be filled in.
  57  * <p>
  58  * <b> Serialization notes:</b>
  59  * <ul>
  60  * <li>The LogRecord class is serializable.
  61  *
  62  * <li> Because objects in the parameters array may not be serializable,
  63  * during serialization all objects in the parameters array are
  64  * written as the corresponding Strings (using Object.toString).
  65  *
  66  * <li> The ResourceBundle is not transmitted as part of the serialized
  67  * form, but the resource bundle name is, and the recipient object's
  68  * readObject method will attempt to locate a suitable resource bundle.
  69  *
  70  * </ul>
  71  *
  72  * @since 1.4
  73  */
  74 
  75 public class LogRecord implements java.io.Serializable {
  76     private static final AtomicLong globalSequenceNumber
  77         = new AtomicLong(0);
  78 
  79     /**
  80      * The default value of threadID will be the current thread's
  81      * thread id, for ease of correlation, unless it is greater than
  82      * MIN_SEQUENTIAL_THREAD_ID, in which case we try harder to keep
  83      * our promise to keep threadIDs unique by avoiding collisions due
  84      * to 32-bit wraparound.  Unfortunately, LogRecord.getThreadID()
  85      * returns int, while Thread.getId() returns long.
  86      */
  87     private static final int MIN_SEQUENTIAL_THREAD_ID = Integer.MAX_VALUE / 2;
  88 
  89     private static final AtomicInteger nextThreadId
  90         = new AtomicInteger(MIN_SEQUENTIAL_THREAD_ID);
  91 
  92     private static final ThreadLocal<Integer> threadIds = new ThreadLocal<>();
  93 
  94     /**
  95      * Logging message level
  96      */
  97     private Level level;
  98 
  99     /**
 100      * Sequence number
 101      */
 102     private long sequenceNumber;
 103 
 104     /**
 105      * Class that issued logging call
 106      */
 107     private String sourceClassName;
 108 
 109     /**
 110      * Method that issued logging call
 111      */
 112     private String sourceMethodName;
 113 
 114     /**
 115      * Non-localized raw message text
 116      */
 117     private String message;
 118 
 119     /**
 120      * Thread ID for thread that issued logging call.
 121      */
 122     private int threadID;
 123 
 124     /**
 125      * The Throwable (if any) associated with log message
 126      */
 127     private Throwable thrown;
 128 
 129     /**
 130      * Name of the source Logger.
 131      */
 132     private String loggerName;
 133 
 134     /**
 135      * Resource bundle name to localized log message.
 136      */
 137     private String resourceBundleName;
 138 
 139     /**
 140      * Event time.
 141      * @since 9
 142      */
 143     private Instant instant;
 144 
 145     /**
 146      * @serialField level Level Logging message level
 147      * @serialField sequenceNumber long Sequence number
 148      * @serialField sourceClassName String Class that issued logging call
 149      * @serialField sourceMethodName String Method that issued logging call
 150      * @serialField message String Non-localized raw message text
 151      * @serialField threadID int Thread ID for thread that issued logging call
 152      * @serialField millis long Truncated event time in milliseconds since 1970
 153      *              - calculated as getInstant().toEpochMilli().
 154      *               The event time instant can be reconstructed using
 155      * <code>Instant.ofEpochSecond(millis/1000, (millis % 1000) * 1000_000 + nanoAdjustment)</code>
 156      * @serialField nanoAdjustment int Nanoseconds adjustment to the millisecond of
 157      *              event time - calculated as getInstant().getNano() % 1000_000
 158      *               The event time instant can be reconstructed using
 159      * <code>Instant.ofEpochSecond(millis/1000, (millis % 1000) * 1000_000 + nanoAdjustment)</code>
 160      *              <p>
 161      *              Since: 9
 162      * @serialField thrown Throwable The Throwable (if any) associated with log
 163      *              message
 164      * @serialField loggerName String Name of the source Logger
 165      * @serialField resourceBundleName String Resource bundle name to localized
 166      *              log message
 167      */
 168     private static final ObjectStreamField[] serialPersistentFields =
 169         new ObjectStreamField[] {
 170             new ObjectStreamField("level", Level.class),
 171             new ObjectStreamField("sequenceNumber", long.class),
 172             new ObjectStreamField("sourceClassName", String.class),
 173             new ObjectStreamField("sourceMethodName", String.class),
 174             new ObjectStreamField("message", String.class),
 175             new ObjectStreamField("threadID", int.class),
 176             new ObjectStreamField("millis", long.class),
 177             new ObjectStreamField("nanoAdjustment", int.class),
 178             new ObjectStreamField("thrown", Throwable.class),
 179             new ObjectStreamField("loggerName", String.class),
 180             new ObjectStreamField("resourceBundleName", String.class),
 181         };
 182 
 183     private transient boolean needToInferCaller;
 184     private transient Object parameters[];
 185     private transient ResourceBundle resourceBundle;
 186 
 187     /**
 188      * Returns the default value for a new LogRecord's threadID.
 189      */
 190     private int defaultThreadID() {
 191         long tid = Thread.currentThread().getId();
 192         if (tid < MIN_SEQUENTIAL_THREAD_ID) {
 193             return (int) tid;
 194         } else {
 195             Integer id = threadIds.get();
 196             if (id == null) {
 197                 id = nextThreadId.getAndIncrement();
 198                 threadIds.set(id);
 199             }
 200             return id;
 201         }
 202     }
 203 
 204     /**
 205      * Construct a LogRecord with the given level and message values.
 206      * <p>
 207      * The sequence property will be initialized with a new unique value.
 208      * These sequence values are allocated in increasing order within a VM.
 209      * <p>
 210      * Since JDK 9, the event time is represented by an {@link Instant}.
 211      * The instant property will be initialized to the {@linkplain
 212      * Instant#now() current instant}, using the best available
 213      * {@linkplain Clock#systemUTC() clock} on the system.
 214      * <p>
 215      * The thread ID property will be initialized with a unique ID for
 216      * the current thread.
 217      * <p>
 218      * All other properties will be initialized to "null".
 219      *
 220      * @param level  a logging level value
 221      * @param msg  the raw non-localized logging message (may be null)
 222      * @see java.time.Clock#systemUTC()
 223      */
 224     public LogRecord(Level level, String msg) {
 225         this.level = Objects.requireNonNull(level);
 226         message = msg;
 227         // Assign a thread ID and a unique sequence number.
 228         sequenceNumber = globalSequenceNumber.getAndIncrement();
 229         threadID = defaultThreadID();
 230         instant = Instant.now();
 231         needToInferCaller = true;
 232    }
 233 
 234     /**
 235      * Get the source Logger's name.
 236      *
 237      * @return source logger name (may be null)
 238      */
 239     public String getLoggerName() {
 240         return loggerName;
 241     }
 242 
 243     /**
 244      * Set the source Logger's name.
 245      *
 246      * @param name   the source logger name (may be null)
 247      */
 248     public void setLoggerName(String name) {
 249         loggerName = name;
 250     }
 251 
 252     /**
 253      * Get the localization resource bundle
 254      * <p>
 255      * This is the ResourceBundle that should be used to localize
 256      * the message string before formatting it.  The result may
 257      * be null if the message is not localizable, or if no suitable
 258      * ResourceBundle is available.
 259      * @return the localization resource bundle
 260      */
 261     public ResourceBundle getResourceBundle() {
 262         return resourceBundle;
 263     }
 264 
 265     /**
 266      * Set the localization resource bundle.
 267      *
 268      * @param bundle  localization bundle (may be null)
 269      */
 270     public void setResourceBundle(ResourceBundle bundle) {
 271         resourceBundle = bundle;
 272     }
 273 
 274     /**
 275      * Get the localization resource bundle name
 276      * <p>
 277      * This is the name for the ResourceBundle that should be
 278      * used to localize the message string before formatting it.
 279      * The result may be null if the message is not localizable.
 280      * @return the localization resource bundle name
 281      */
 282     public String getResourceBundleName() {
 283         return resourceBundleName;
 284     }
 285 
 286     /**
 287      * Set the localization resource bundle name.
 288      *
 289      * @param name  localization bundle name (may be null)
 290      */
 291     public void setResourceBundleName(String name) {
 292         resourceBundleName = name;
 293     }
 294 
 295     /**
 296      * Get the logging message level, for example Level.SEVERE.
 297      * @return the logging message level
 298      */
 299     public Level getLevel() {
 300         return level;
 301     }
 302 
 303     /**
 304      * Set the logging message level, for example Level.SEVERE.
 305      * @param level the logging message level
 306      */
 307     public void setLevel(Level level) {
 308         if (level == null) {
 309             throw new NullPointerException();
 310         }
 311         this.level = level;
 312     }
 313 
 314     /**
 315      * Get the sequence number.
 316      * <p>
 317      * Sequence numbers are normally assigned in the LogRecord
 318      * constructor, which assigns unique sequence numbers to
 319      * each new LogRecord in increasing order.
 320      * @return the sequence number
 321      */
 322     public long getSequenceNumber() {
 323         return sequenceNumber;
 324     }
 325 
 326     /**
 327      * Set the sequence number.
 328      * <p>
 329      * Sequence numbers are normally assigned in the LogRecord constructor,
 330      * so it should not normally be necessary to use this method.
 331      * @param seq the sequence number
 332      */
 333     public void setSequenceNumber(long seq) {
 334         sequenceNumber = seq;
 335     }
 336 
 337     /**
 338      * Get the  name of the class that (allegedly) issued the logging request.
 339      * <p>
 340      * Note that this sourceClassName is not verified and may be spoofed.
 341      * This information may either have been provided as part of the
 342      * logging call, or it may have been inferred automatically by the
 343      * logging framework.  In the latter case, the information may only
 344      * be approximate and may in fact describe an earlier call on the
 345      * stack frame.
 346      * <p>
 347      * May be null if no information could be obtained.
 348      *
 349      * @return the source class name
 350      */
 351     public String getSourceClassName() {
 352         if (needToInferCaller) {
 353             inferCaller();
 354         }
 355         return sourceClassName;
 356     }
 357 
 358     /**
 359      * Set the name of the class that (allegedly) issued the logging request.
 360      *
 361      * @param sourceClassName the source class name (may be null)
 362      */
 363     public void setSourceClassName(String sourceClassName) {
 364         this.sourceClassName = sourceClassName;
 365         needToInferCaller = false;
 366     }
 367 
 368     /**
 369      * Get the  name of the method that (allegedly) issued the logging request.
 370      * <p>
 371      * Note that this sourceMethodName is not verified and may be spoofed.
 372      * This information may either have been provided as part of the
 373      * logging call, or it may have been inferred automatically by the
 374      * logging framework.  In the latter case, the information may only
 375      * be approximate and may in fact describe an earlier call on the
 376      * stack frame.
 377      * <p>
 378      * May be null if no information could be obtained.
 379      *
 380      * @return the source method name
 381      */
 382     public String getSourceMethodName() {
 383         if (needToInferCaller) {
 384             inferCaller();
 385         }
 386         return sourceMethodName;
 387     }
 388 
 389     /**
 390      * Set the name of the method that (allegedly) issued the logging request.
 391      *
 392      * @param sourceMethodName the source method name (may be null)
 393      */
 394     public void setSourceMethodName(String sourceMethodName) {
 395         this.sourceMethodName = sourceMethodName;
 396         needToInferCaller = false;
 397     }
 398 
 399     /**
 400      * Get the "raw" log message, before localization or formatting.
 401      * <p>
 402      * May be null, which is equivalent to the empty string "".
 403      * <p>
 404      * This message may be either the final text or a localization key.
 405      * <p>
 406      * During formatting, if the source logger has a localization
 407      * ResourceBundle and if that ResourceBundle has an entry for
 408      * this message string, then the message string is replaced
 409      * with the localized value.
 410      *
 411      * @return the raw message string
 412      */
 413     public String getMessage() {
 414         return message;
 415     }
 416 
 417     /**
 418      * Set the "raw" log message, before localization or formatting.
 419      *
 420      * @param message the raw message string (may be null)
 421      */
 422     public void setMessage(String message) {
 423         this.message = message;
 424     }
 425 
 426     /**
 427      * Get the parameters to the log message.
 428      *
 429      * @return the log message parameters.  May be null if
 430      *                  there are no parameters.
 431      */
 432     public Object[] getParameters() {
 433         return parameters;
 434     }
 435 
 436     /**
 437      * Set the parameters to the log message.
 438      *
 439      * @param parameters the log message parameters. (may be null)
 440      */
 441     public void setParameters(Object parameters[]) {
 442         this.parameters = parameters;
 443     }
 444 
 445     /**
 446      * Get an identifier for the thread where the message originated.
 447      * <p>
 448      * This is a thread identifier within the Java VM and may or
 449      * may not map to any operating system ID.
 450      *
 451      * @return thread ID
 452      */
 453     public int getThreadID() {
 454         return threadID;
 455     }
 456 
 457     /**
 458      * Set an identifier for the thread where the message originated.
 459      * @param threadID  the thread ID
 460      */
 461     public void setThreadID(int threadID) {
 462         this.threadID = threadID;
 463     }
 464 
 465     /**
 466      * Get truncated event time in milliseconds since 1970.
 467      *
 468      * @return truncated event time in millis since 1970
 469      *
 470      * @implSpec This is equivalent to calling
 471      *      {@link #getInstant() getInstant().toEpochMilli()}.
 472      *
 473      * @apiNote To get the full nanosecond resolution event time,
 474      *             use {@link #getInstant()}.
 475      *
 476      * @see #getInstant()
 477      */
 478     public long getMillis() {
 479         return instant.toEpochMilli();
 480     }
 481 
 482     /**
 483      * Set event time.
 484      *
 485      * @param millis event time in millis since 1970.
 486      *
 487      * @implSpec This is equivalent to calling
 488      *      {@link #setInstant(java.time.Instant)
 489      *      setInstant(Instant.ofEpochMilli(millis))}.
 490      *
 491      * @deprecated LogRecord maintains timestamps with nanosecond resolution,
 492      *             using {@link Instant} values. For this reason,
 493      *             {@link #setInstant(java.time.Instant) setInstant()}
 494      *             should be used in preference to {@code setMillis()}.
 495      *
 496      * @see #setInstant(java.time.Instant)
 497      */
 498     @Deprecated
 499     public void setMillis(long millis) {
 500         this.instant = Instant.ofEpochMilli(millis);
 501     }
 502 
 503     /**
 504      * Gets the instant that the event occurred.
 505      *
 506      * @return the instant that the event occurred.
 507      *
 508      * @since 9
 509      */
 510     public Instant getInstant() {
 511         return instant;
 512     }
 513 
 514     /**
 515      * Sets the instant that the event occurred.
 516      * <p>
 517      * If the given {@code instant} represents a point on the time-line too
 518      * far in the future or past to fit in a {@code long} milliseconds and
 519      * nanoseconds adjustment, then an {@code ArithmeticException} will be
 520      * thrown.
 521      *
 522      * @param instant the instant that the event occurred.
 523      *
 524      * @throws NullPointerException if {@code instant} is null.
 525      * @throws ArithmeticException if numeric overflow would occur while
 526      *         calling {@link Instant#toEpochMilli() instant.toEpochMilli()}.
 527      *
 528      * @since 9
 529      */
 530     public void setInstant(Instant instant) {
 531         instant.toEpochMilli();
 532         this.instant = instant;
 533     }
 534 
 535     /**
 536      * Get any throwable associated with the log record.
 537      * <p>
 538      * If the event involved an exception, this will be the
 539      * exception object. Otherwise null.
 540      *
 541      * @return a throwable
 542      */
 543     public Throwable getThrown() {
 544         return thrown;
 545     }
 546 
 547     /**
 548      * Set a throwable associated with the log event.
 549      *
 550      * @param thrown  a throwable (may be null)
 551      */
 552     public void setThrown(Throwable thrown) {
 553         this.thrown = thrown;
 554     }
 555 
 556     private static final long serialVersionUID = 5372048053134512534L;
 557 
 558     /**
 559      * @serialData Serialized fields, followed by a two byte version number
 560      * (major byte, followed by minor byte), followed by information on
 561      * the log record parameter array.  If there is no parameter array,
 562      * then -1 is written.  If there is a parameter array (possible of zero
 563      * length) then the array length is written as an integer, followed
 564      * by String values for each parameter.  If a parameter is null, then
 565      * a null String is written.  Otherwise the output of Object.toString()
 566      * is written.
 567      */
 568     private void writeObject(ObjectOutputStream out) throws IOException {
 569         // We have to write serialized fields first.
 570         ObjectOutputStream.PutField pf = out.putFields();
 571         pf.put("level", level);
 572         pf.put("sequenceNumber", sequenceNumber);
 573         pf.put("sourceClassName", sourceClassName);
 574         pf.put("sourceMethodName", sourceMethodName);
 575         pf.put("message", message);
 576         pf.put("threadID", threadID);
 577         pf.put("millis", instant.toEpochMilli());
 578         pf.put("nanoAdjustment", instant.getNano() % 1000_000);
 579         pf.put("thrown", thrown);
 580         pf.put("loggerName", loggerName);
 581         pf.put("resourceBundleName", resourceBundleName);
 582         out.writeFields();
 583 
 584         // Write our version number.
 585         out.writeByte(1);
 586         out.writeByte(0);
 587         if (parameters == null) {
 588             out.writeInt(-1);
 589             return;
 590         }
 591         out.writeInt(parameters.length);
 592         // Write string values for the parameters.
 593         for (Object parameter : parameters) {
 594             out.writeObject(Objects.toString(parameter, null));
 595         }
 596     }
 597 
 598     private void readObject(ObjectInputStream in)
 599                         throws IOException, ClassNotFoundException {
 600         // We have to read serialized fields first.
 601         ObjectInputStream.GetField gf = in.readFields();
 602         level = (Level) gf.get("level", null);
 603         sequenceNumber = gf.get("sequenceNumber", 0L);
 604         sourceClassName = (String) gf.get("sourceClassName", null);
 605         sourceMethodName = (String) gf.get("sourceMethodName", null);
 606         message = (String) gf.get("message", null);
 607         threadID = gf.get("threadID", 0);
 608         long millis = gf.get("millis", 0L);
 609         int nanoOfMilli = gf.get("nanoAdjustment", 0);
 610         instant = Instant.ofEpochSecond(
 611             millis / 1000L, (millis % 1000L) * 1000_000L + nanoOfMilli);
 612         thrown = (Throwable) gf.get("thrown", null);
 613         loggerName = (String) gf.get("loggerName", null);
 614         resourceBundleName = (String) gf.get("resourceBundleName", null);
 615 
 616         // Read version number.
 617         byte major = in.readByte();
 618         byte minor = in.readByte();
 619         if (major != 1) {
 620             throw new IOException("LogRecord: bad version: " + major + "." + minor);
 621         }
 622         int len = in.readInt();
 623         if (len == -1) {
 624             parameters = null;
 625         } else {
 626             parameters = new Object[len];
 627             for (int i = 0; i < parameters.length; i++) {
 628                 parameters[i] = in.readObject();
 629             }
 630         }
 631         // If necessary, try to regenerate the resource bundle.
 632         if (resourceBundleName != null) {
 633             try {
 634                 // use system class loader to ensure the ResourceBundle
 635                 // instance is a different instance than null loader uses
 636                 final ResourceBundle bundle =
 637                         ResourceBundle.getBundle(resourceBundleName,
 638                                 Locale.getDefault(),
 639                                 ClassLoader.getSystemClassLoader());
 640                 resourceBundle = bundle;
 641             } catch (MissingResourceException ex) {
 642                 // This is not a good place to throw an exception,
 643                 // so we simply leave the resourceBundle null.
 644                 resourceBundle = null;
 645             }
 646         }
 647 
 648         needToInferCaller = false;
 649     }
 650 
 651     // Private method to infer the caller's class and method names
 652     //
 653     // Note:
 654     // For testing purposes - it is possible to customize the process
 655     // by which LogRecord will infer the source class name and source method name
 656     // when analyzing the call stack.
 657     // <p>
 658     // The system property {@code jdk.logger.packages} can define a comma separated
 659     // list of strings corresponding to additional package name prefixes that
 660     // should be ignored when trying to infer the source caller class name.
 661     // Those stack frames whose {@linkplain StackTraceElement#getClassName()
 662     // declaring class name} start with one such prefix will be ignored.
 663     // <p>
 664     // This is primarily useful when providing utility logging classes wrapping
 665     // a logger instance, as it makes it possible to instruct LogRecord to skip
 666     // those utility frames when inferring the caller source class name.
 667     // <p>
 668     // The {@code jdk.logger.packages} system property is consulted only once.
 669     // <p>
 670     // This property is not standard, implementation specific, and yet
 671     // undocumented (and thus subject to changes without notice).
 672     //
 673     private void inferCaller() {
 674         needToInferCaller = false;
 675         // Skip all frames until we have found the first logger frame.
 676         Optional<StackWalker.StackFrame> frame = new CallerFinder().get();
 677         frame.ifPresent(f -> {
 678             setSourceClassName(f.getClassName());
 679             setSourceMethodName(f.getMethodName());
 680         });
 681 
 682         // We haven't found a suitable frame, so just punt.  This is
 683         // OK as we are only committed to making a "best effort" here.
 684     }
 685 
 686     /*
 687      * CallerFinder is a stateful predicate.
 688      */
 689     static final class CallerFinder implements Predicate<StackWalker.StackFrame> {
 690         private static final StackWalker WALKER;
 691         static {
 692             final PrivilegedAction<StackWalker> action =
 693                     () -> StackWalker.getInstance(StackWalker.Option.RETAIN_CLASS_REFERENCE);
 694             WALKER = AccessController.doPrivileged(action);
 695         }
 696 
 697         /**
 698          * Returns StackFrame of the caller's frame.
 699          * @return StackFrame of the caller's frame.
 700          */
 701         Optional<StackWalker.StackFrame> get() {
 702             return WALKER.walk((s) -> s.filter(this).findFirst());
 703         }
 704 
 705         private boolean lookingForLogger = true;
 706         /**
 707          * Returns true if we have found the caller's frame, false if the frame
 708          * must be skipped.
 709          *
 710          * @param t The frame info.
 711          * @return true if we have found the caller's frame, false if the frame
 712          * must be skipped.
 713          */
 714         @Override
 715         public boolean test(StackWalker.StackFrame t) {
 716             final String cname = t.getClassName();
 717             // We should skip all frames until we have found the logger,
 718             // because these frames could be frames introduced by e.g. custom
 719             // sub classes of Handler.
 720             if (lookingForLogger) {
 721                 // the log record could be created for a platform logger
 722                 lookingForLogger = !isLoggerImplFrame(cname);
 723                 return false;
 724             }
 725             // Continue walking until we've found the relevant calling frame.
 726             // Skips logging/logger infrastructure.
 727             return !isFilteredFrame(t);
 728         }
 729 
 730         private boolean isLoggerImplFrame(String cname) {
 731             return (cname.equals("java.util.logging.Logger") ||
 732                     cname.startsWith("sun.util.logging.PlatformLogger"));
 733         }
 734     }
 735 }