Why does main thread here doesn’t wait for t2? Here the output always is always more than 20000 but not consistent

package org.multithreading.basics; public class ThreadJoin { public static void main(String[] args) { Counter counter = new Counter(); Thread t1 = new Thread(counter); Thread t2 = new Thread(counter); t1.start(); t2.start(); try { t1.join(); t2.join(); } catch (InterruptedException e) { e.printStackTrace(); } System.out.println(“Numbers counted =” + counter.getCount()); } } class Counter implements Runnable { private int count;…

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Why does epoll use a red-black tree to manage file descriptors rather than a hash table?

The linux system call epoll_ctl (at fs/eventpoll.c) uses a red-black tree known as the interest list to create, remove, or modify interest in events of a file descriptor. The interest list is not searched by epoll_wait, which rather waits for callbacks from poll (at include/linux/poll.h). Therefore, the execution time of epoll to receive interesting file…

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Does a trusted blockchain import from BitcoinCore require that chainstate and blocks be from the same source?

Can the chainstate folder from a pruned node be used with the blocks folder from a full node to provide the full blockchain? Assume that both nodes have been running for months. If the blocks folder contains references to filenames in the chainstate folder, then the answer is no. I know this because the filenames…

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How do I fix a dpkg “Bad Message” error when trying to upgrade python3-software-properties?

I’m unable to upgrade my Ubuntu 18.04.3 LTS system due to error “unable to install (supposed) new info file ‘/var/lib/dpkg/tmp.ci/md5sums’: Bad message” when trying to upgrade package python3-software-properties. The full upgrade output is: $ sudo apt full-upgrade Reading package lists… Done Building dependency tree Reading state information… Done Calculating upgrade… Done The following packages will…

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