How can I get the whole thread name when I use `ps -T -p [pid]`

Question

ps -T -p [pid] and top -H -p [pid] can only display the first 15 characters like http-nio-8080-e, but I would like to get the whole thread name like http-nio-8080-exec-9, What should I do? thank you!

for example:

[root@localhost ~]# ps -T -p 2251
  PID  SPID TTY          TIME CMD
 2251  2251 ?        00:00:00 java
 2251  2808 ?        00:00:03 java
 2251  2821 ?        00:00:00 VM Thread
 2251  2822 ?        00:00:00 Reference Handl
 2251  2823 ?        00:00:00 Finalizer
 2251  2824 ?        00:00:00 Signal Dispatch
 2251  2825 ?        00:00:02 C2 CompilerThre
 2251  2832 ?        00:00:02 C1 CompilerThre
 2251  2835 ?        00:00:00 Sweeper thread
 2251  2851 ?        00:00:00 Service Thread
 2251  2866 ?        00:00:00 VM Periodic Tas
 2251  2867 ?        00:00:00 Common-Cleaner
 2251  6518 ?        00:00:00 Catalina-utilit
 2251  6520 ?        00:00:00 Catalina-utilit
 2251  6531 ?        00:00:00 container-0
 2251  7370 ?        00:00:00 NioBlockingSele
 2251  7374 ?        00:00:00 http-nio-8080-e
 2251  7375 ?        00:00:00 http-nio-8080-e
 2251  7376 ?        00:00:00 http-nio-8080-e
 2251  7377 ?        00:00:00 http-nio-8080-e
 2251  7378 ?        00:00:00 http-nio-8080-e
 2251  7379 ?        00:00:00 http-nio-8080-e
 2251  7380 ?        00:00:00 http-nio-8080-e
 2251  7381 ?        00:00:00 http-nio-8080-e
 2251  7382 ?        00:00:00 http-nio-8080-e
 2251  7383 ?        00:00:00 http-nio-8080-e
 2251  7384 ?        00:00:00 http-nio-8080-C
 2251  7395 ?        00:00:00 http-nio-8080-A

and

[root@localhost ~]# top -H -p 2251
top - 12:00:38 up 15 min,  1 user,  load average: 0.06, 0.11, 0.19
Threads:  28 total,   0 running,  28 sleeping,   0 stopped,   0 zombie
%Cpu(s):  0.0 us,  0.0 sy,  0.0 ni,100.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
KiB Mem :  3880412 total,  2276824 free,   903836 used,   699752 buff/cache
KiB Swap:  1581052 total,  1581052 free,        0 used.  2745864 avail Mem

  PID USER      PR  NI    VIRT    RES    SHR S %CPU %MEM     TIME+ COMMAND
 2251 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.07 java
 2808 root      20   0 3043676 152880  14232 S  0.0  3.9   0:03.00 java
 2821 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.27 VM Thread
 2822 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.00 Reference Handl
 2823 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.00 Finalizer
 2824 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.00 Signal Dispatch
 2825 root      20   0 3043676 152880  14232 S  0.0  3.9   0:02.76 C2 CompilerThre
 2832 root      20   0 3043676 152880  14232 S  0.0  3.9   0:02.07 C1 CompilerThre
 2835 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.01 Sweeper thread
 2851 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.00 Service Thread
 2866 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.74 VM Periodic Tas
 2867 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.00 Common-Cleaner
 6518 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.02 Catalina-utilit
 6520 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.12 Catalina-utilit
 6531 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.00 container-0
 7370 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.05 NioBlockingSele
 7374 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.14 http-nio-8080-e
 7375 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.00 http-nio-8080-e
 7376 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.03 http-nio-8080-e
 7377 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.00 http-nio-8080-e
 7378 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.00 http-nio-8080-e
 7379 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.00 http-nio-8080-e
 7380 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.00 http-nio-8080-e
 7381 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.00 http-nio-8080-e
 7382 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.00 http-nio-8080-e
 7383 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.00 http-nio-8080-e
 7384 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.06 http-nio-8080-C
 7395 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.00 http-nio-8080-A

It can only display the first 15 characters like http-nio-8080-e, I would like to get the whole thread name like http-nio-8080-exec-9, What should I do?

"http-nio-8080-exec-9" #25 daemon prio=5 os_prio=0 cpu=0.13ms elapsed=1013.48s tid=0x00007fc0708d9000 nid=0x1f waiting on condition  [0x00007fc0506b1000]
   java.lang.Thread.State: WAITING (parking)
        at jdk.internal.misc.Unsafe.park([email protected]/Native Method)
        - parking to wait for  <0x00000000c5c22c20> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
        at java.util.concurrent.locks.LockSupport.park([email protected]/LockSupport.java:194)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await([email protected]/AbstractQueuedSynchronizer.java:2081)
        at java.util.concurrent.LinkedBlockingQueue.take([email protected]/LinkedBlockingQueue.java:433)
        at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:107)
        at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:33)
        at java.util.concurrent.ThreadPoolExecutor.getTask([email protected]/ThreadPoolExecutor.java:1054)
        at java.util.concurrent.ThreadPoolExecutor.runWorker([email protected]/ThreadPoolExecutor.java:1114)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run([email protected]/ThreadPoolExecutor.java:628)
        at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
        at java.lang.Thread.run([email protected]/Thread.java:834)

Answer 1

The thread name length is restricted to 16 characters (including the terminating null byte \0). If the length, including the \0, exceeds 16 bytes, the string is silently truncated before storing it.

See pthread_setname_np and proc.5 -> find /proc/[pid]/task/[tid]/comm.

Related:
How to get the full executable name of a running process in Linux