Exception ClassNotFoundException



java.lang.ClassNotFoundException org.bouncycastle.jce.provider.BouncyCastleProvider






Stackoverflow can be source of great knowledge ~ with some reading. I was doing some tests with thread dumps in EAP JBoss, analyzing some here and there. Then I came to this tool: lscpu.


Lscpu man page displays the information about the CPU, as below:

[fdemeloj@fdemeloj home]$ lscpu 
Architecture:          x86_64
CPU op-mode(s):        32-bit, 64-bit
Byte Order:            Little Endian
CPU(s):                8
On-line CPU(s) list:   0-7
Thread(s) per core:    2
Core(s) per socket:    4
Socket(s):             1
NUMA node(s):          1
Vendor ID:             GenuineIntel
CPU family:            6
Model:                 142
Model name:            Intel(R) Core(TM) i7-8650U CPU @ 1.90GHz
Stepping:              10
CPU MHz:               797.497
CPU max MHz:           4200.0000
CPU min MHz:           400.0000
BogoMIPS:              4224.00
Virtualization:        VT-x
L1d cache:             32K
L1i cache:             32K
L2 cache:              256K
L3 cache:              8192K
NUMA node0 CPU(s):     0-7
Flags:                 fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc art arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf eagerfpu pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch epb intel_pt tpr_shadow vnmi flexpriority ept vpid fsgsbase tsc_adjust bmi1 hle avx2 smep bmi2 erms invpcid rtm mpx rdseed adx smap clflushopt xsaveopt xsavec xgetbv1 ibpb ibrs stibp dtherm ida arat pln pts hwp hwp_notify hwp_act_window hwp_epp spec_ctrl intel_stibp

The information

CPU The logical CPU number of a CPU as used by the Linux kernel.

CORE The logical core number. A core can contain several CPUs.

SOCKET The logical socket number. A socket can contain several cores.

BOOK The logical book number. A book can contain several sockets.

NODE The logical NUMA node number. A node may contain several books.

CACHE Information about how caches are shared between CPUs.

ADDRESS The physical address of a CPU.

ONLINE  Indicator that shows whether the Linux instance currently makes use of the CPU.


   Original question Stackoverflow

rngd ~ Red Hat random number generator



~ rngd  is this tool to change the Random number generator, which is related to several other tools/mechanisms for example: SSH keys, random PIDs for processes, TCP sequence numbers, and UUIDs.

  This daemon feeds data from a random number generator to the kernel’s random number entropy pool, after first checking the data to ensure that it is properly random.



yum install rng-tools

   rngd is a program within rng-tools


rngd -f

  An interesting tutorial can be found here


Linux man

Viewing/Changing content on app CLI JBoss EAP



Can I read the content from an application using the cli command? Yes.

Reading content with CLI command

[standalone@localhost:9990 /] /deployment=hibernate.war:read-content(path=index.html)
    "outcome" => "success",
    "result" => {"uuid" => "06519ccf-24d4-4b6f-9be1-aa859f98a538"},
    "response-headers" => {"attached-streams" => [{
        "uuid" => "06519ccf-24d4-4b6f-9be1-aa859f98a538",
        "mime-type" => "text/html"

But to read you will need <attachment display>

attachment display --operation=/deployment=hibernate.war:read-content(path=index.html)

The content will be shown as:

<!-- Plain HTML page that kicks us into the app -->

<meta http-equiv="Refresh" content="0; URL=index.jsf">


    Original question