The usual reason for using char[] instead of String is so you can overwrite it in heap without having to wait for garbage collection and is only used for security reasons (e.g., a password). I'm going to guess legacy reasons for the char[], but native code could make sense, too.
On 15 February 2017 at 22:21, Remko Popma <remko.po...@gmail.com> wrote: > Hi Leon, > > Yes by default the thread name is cached. > There is a system property to switch that off: see > https://github.com/apache/logging-log4j2/blob/master/ > log4j-core/src/main/java/org/apache/logging/log4j/core/async/ > ThreadNameCachingStrategy.java > > The reason for the caching is that every call to get the current thread's > name creates a new String object, which I found impacted performance > measurably. > > Why Thread is implemented to store its name in a char[] array and create a > new String on each query I don't know. May have to do with interaction with > native code. > > Remko > > Sent from my iPhone > > On Feb 16, 2017, at 4:37, Leon Finker <leon...@gmail.com> wrote: > > Hi, > > Is there any thread name caching going on with log4j2 (doesn't matter > sync/async)? If I have a thread pool of tasks and call > Thread.currentThread().setName (with unique id) in the beginning of the > task execution, I sometimes see reuse of previous thread name in the log > statements. Id is UUID, so it's definitely unique. And if I do System.out > on the current thread name after setting it, I do see the new name as > expected. But in log statements the thread name is from the previous set. > The pattern layout is: [%date{DEFAULT}{UTC}Z][%level][%thread:%tid][%c{3}] > %message%n > > log4j:2.7 > > Any ideas what could be causing the thread name reuse? > > Thank you > > --------------------------------------------------------------------- > To unsubscribe, e-mail: log4j-dev-unsubscr...@logging.apache.org > For additional commands, e-mail: log4j-dev-h...@logging.apache.org > > -- Matt Sicker <boa...@gmail.com>
