The thread that is holding on to lock seems to be writing to console – based on the stack which shows consoleTarget java and I do have a ConsoleAppender

"pool-6-thread-87" #129 prio=5 os_prio=0 tid=0x00007f90d405d000 nid=0xb6 runnable [0x00007f8fd73f2000]

   java.lang.Thread.State: RUNNABLE

        at java.io.FileOutputStream.writeBytes(Native Method)

        at java.io.FileOutputStream.write(FileOutputStream.java:326)

        at java.io.BufferedOutputStream.write(BufferedOutputStream.java:122)

        - locked <0x00000003c06e8890> (a java.io.BufferedOutputStream)

        at java.io.PrintStream.write(PrintStream.java:480)

        - locked <0x00000003c06e8870> (a java.io.PrintStream)

        at java.io.FilterOutputStream.write(FilterOutputStream.java:97)

        at ch.qos.logback.core.joran.spi.ConsoleTarget$1.write(ConsoleTarget.java:37)