Adds a getSingleton method expected by SLF4J

[bric3]

SLF4J introduced the change in 1.7.14, see https://github.com/qos-ch/slf4j/blob/v_1.7.21/slf4j-api/src/main/java/org/slf4j/MDC.java#L88-L104 The StaticLoggerBinder is up to date but not StaticMDCBinder

[bric3]

It seems the CI failure is time related

monthlyRolloverOverManyPeriods(ch.qos.logback.core.rolling.TimeBasedRollingWithArchiveRemoval_Test)  Time elapsed: 0.417 sec

checkCrossedPeriodsWithDSTBarrier(ch.qos.logback.core.rolling.TimeBasedRollingWithArchiveRemoval_Test)  Time elapsed: 0.06 sec

checkCleanupForBasicDailyRollover(ch.qos.logback.core.rolling.TimeBasedRollingWithArchiveRemoval_Test)  Time elapsed: 0.159 sec

checkCleanupForBasicDailyRolloverWithSizeCap(ch.qos.logback.core.rolling.TimeBasedRollingWithArchiveRemoval_Test)  Time elapsed: 0.05 sec

checkThatSmallTotalSizeCapLeavesAtLeastOneArhcive(ch.qos.logback.core.rolling.TimeBasedRollingWithArchiveRemoval_Test)  Time elapsed: 0.037 sec  <<< FAILURE!

java.lang.AssertionError: expected:<1> but was:<0>

    at org.junit.Assert.fail(Assert.java:93)

    at org.junit.Assert.failNotEquals(Assert.java:647)

    at org.junit.Assert.assertEquals(Assert.java:128)

    at org.junit.Assert.assertEquals(Assert.java:472)

    at org.junit.Assert.assertEquals(Assert.java:456)

    at ch.qos.logback.core.rolling.TimeBasedRollingWithArchiveRemoval_Test.checkFileCount(TimeBasedRollingWithArchiveRemoval_Test.java:484)

    at ch.qos.logback.core.rolling.TimeBasedRollingWithArchiveRemoval_Test.checkThatSmallTotalSizeCapLeavesAtLeastOneArhcive(TimeBasedRollingWithArchiveRemoval_Test.java:191)

    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)

    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

    at java.lang.reflect.Method.invoke(Method.java:606)

    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:45)

    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)

    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:42)

    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)

    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)

    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:263)

    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:68)

    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:47)

    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231)

    at org.apache.maven.surefire.junitcore.pc.Scheduler$1.run(Scheduler.java:393)

    at org.apache.maven.surefire.junitcore.pc.InvokerStrategy.schedule(InvokerStrategy.java:54)

    at org.apache.maven.surefire.junitcore.pc.Scheduler.schedule(Scheduler.java:352)

    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:229)

    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:50)

    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:222)

    at org.junit.runners.ParentRunner.run(ParentRunner.java:300)

    at org.junit.runners.Suite.runChild(Suite.java:128)

    at org.junit.runners.Suite.runChild(Suite.java:24)

    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231)

    at org.apache.maven.surefire.junitcore.pc.Scheduler$1.run(Scheduler.java:393)

    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)

    at java.util.concurrent.FutureTask.run(FutureTask.java:262)

    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)

    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)

    at java.lang.Thread.run(Thread.java:745)

[diroussel]

Can the build be retriggered?