Clever Geek Handbook

Apa yang disiapkan oleh pihak ketiga .jar untuk kita ...

Saya akan memberi tahu Anda tentang satu insiden lucu yang membuat seluruh tim kita berkeringat banyak, dan hampir membuat beberapa menjadi gugup. Penelitian telah menghasilkan alat yang efektif yang dapat digunakan pengembang mana pun untuk membuat tim lainnya gelisah. Inti dari posting ini adalah untuk memperingatkan tentang kemungkinan situasi non-sepele dan bersiap untuk mereka.





Penyimpangan lirik



, . open-source , - , , , . , . , . . , . , work-around, , .



:



  • . , .
  • . , , . , , , StackOverflow.
  • , , .
  • . , . : , “ ” .
  • . , .


.





, . , , SFTP .



:



public class Task implements Runnable {
    static final Logger log = LoggerFactory.getLogger(Task.class);

    public void run() {
        log.info("Task started");
        try(var remoteFile = createRemoteFile(xxx)) {
            this.setState(STARTED);
            for (int page = 0;;page++) {
                var block = service.requestDataBlock(page);
                if (block == null) break;
                transformData(block);
                remoteFile.writeDataBlock(block);
            }
            this.setState(FINISHED);
            log.info("Task finished");
        } catch (Exception ex) {
            log.error("Task failed", ex);
            this.setState(ERROR);
        }
    }
}


, , state=STARTED . — - . "Task started", "Task finished" "Task failed".



1



, , . — - dead lock. , thread dump , . .



2



, thread dump, , — . - "Task started", "Task finished" "Task failed"! , , Throwable Error, Exception. catch(Exception) catch(Throwable) . — , thread dump- .



3



, . , , thread dump, , . - . , . !



4



— , — , . , - OutOfMemoryError, catch ( OutOfMemoryError). java -XX:+CrashOnOutOfMemoryError -XX:+HeapDumpOnOutOfMemoryError. java- OutOfMemory hs_err_pid, — memory dump . : OutOfMemory — ( ), , .



5



. : , ! - Thread.stop(), , - JDK. — , , - , . System.out.println(), try-catch . :



java.lang.StackOverflowError
    at java.lang.reflect.InvocationTargetException.<init>(InvocationTargetException.java:72)
    at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at ch.qos.logback.classic.spi.ThrowableProxy.<init>(ThrowableProxy.java:66)
    at ch.qos.logback.classic.spi.ThrowableProxy.<init>(ThrowableProxy.java:72)
    at ch.qos.logback.classic.spi.ThrowableProxy.<init>(ThrowableProxy.java:72)
    at ch.qos.logback.classic.spi.ThrowableProxy.<init>(ThrowableProxy.java:72)
    at ch.qos.logback.classic.spi.ThrowableProxy.<init>(ThrowableProxy.java:72)
    at ch.qos.logback.classic.spi.ThrowableProxy.<init>(ThrowableProxy.java:72)
            ...


! , Logback. , , — Error, ! , :



log.error("Task failed", ex);




What a Terrible Failure (WTF?!)



- ? ThrowableProxy Logback , suppressed exceptions, :



suppressed = new ThrowableProxy[throwableSuppressed.length];
for (int i = 0; i < throwableSuppressed.length; i++) {
   this.suppressed[i] = new ThrowableProxy(throwableSuppressed[i]);
   this.suppressed[i].commonFrames = 
        ThrowableProxyUtil.findNumberOfCommonFrames(throwableSuppressed[i].getStackTrace(),
                   stackTraceElementProxyArray);
}


, suppressed exceptions . :



@Test
public void testLogback() throws Exception {
    Logger log = LoggerFactory.getLogger(TestLogback.class);
    //    java 
    // java.lang.IllegalArgumentException: Self-suppression not permitted
    //ex.addSuppressed(ex);
    //   
    Exception ex = new Exception("Test exception");
    Exception ex1 = new Exception("Test exception1");
    ex.addSuppressed(ex1);
    ex1.addSuppressed(ex);
    log.error("Exception", ex);
}


— StackOverflowError! Java, ( 19000 maven-) , , . Logback , SFTP — Apache VFS. IOException suppressed, IOException. .



Logback ? , 2014 :

https://jira.qos.ch/browse/LOGBACK-1027

2019:

https://jira.qos.ch/browse/LOGBACK-1454

.



, Java ? , ex.printStackTrace(), , CIRCULAR REFERENCE:



java.io.IOException: Test exception
    at org.example.test.TestLogback.lambda$testJavaOutput$1(TestLogback.java:43)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)
    Suppressed: java.lang.Exception: Test exception1
        at org.example.test.TestLogback.lambda$testJavaOutput$1(TestLogback.java:44)
        ... 5 more
    [CIRCULAR REFERENCE:java.lang.Exception: Test exception]


java.util.logging.



Log4j , suppressed exception.



14:15:22.154 [main] ERROR org.example.test.TestLogback - Test
java.lang.Exception: Test exception
    at org.example.test.TestLogback.testLog4j(TestLogback.java:61) [test-classes/:?]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_251]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_251]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_251]
    at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_251]
    Suppressed: java.lang.Exception: Test exception1
        at org.example.test.TestLogback.testLog4j(TestLogback.java:62) [test-classes/:?]
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_251]
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_251]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_251]
        at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_251]
        Suppressed: java.lang.Exception: Test exception
            at org.example.test.TestLogback.testLog4j(TestLogback.java:61) [test-classes/:?]
            at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_251]
            at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_251]
            at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_251]
            at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_251]




Logback — . , :



  • , , , . .
  • , , .
  • , .
  • , .
  • Jangan berharap tiket Anda diperbaiki dengan cepat atau permintaan tarik cepat diterima - perlu beberapa bulan hingga beberapa tahun sebelum perbaikan dipublikasikan di repositori resmi.
  • Jika Anda menggunakan Logback, sesuaikan pengecualian dengan menghapus referensi melingkar sebelum masuk log. Ini hanya dapat dilakukan di penangan tingkat atas di Thread dan ExecutorService.


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