Fundamentals of Concurrent Programming
Root Causes of Concurrency Issues
Visibility
Visibility refers to the ability of a thread to immediately observe changes made to shared variables by other threads. The fundamental problem stems from CPU cache architectures.
// Thread A executes
int counter = 0;
counter = 42;
// Thread B executes
int result = counter;
When Thread A executes c ...
Posted on Sun, 31 May 2026 23:21:42 +0000 by fris
Essential Java Interview Topics and Concepts
Java Primitive Types
Java supports eight primitive data types:
8-bit: byte
16-bit: short, char
32-bit: int, float
64-bit: long, double
boolean
Java Data Structures
Arrays
Arrays offer O(1) access time via index, making them excellent for random access operations and sequential iteration. However, their size is fixed at creation time, preventi ...
Posted on Sat, 16 May 2026 08:47:52 +0000 by Someone789
Troubleshooting Java DNS Cache NullPointerException in Multi-threaded Environments
Exception Manifestation
2018-03-16 18:53:59,501 ERROR [DefaultMessageListenerContainer-1] (com.bill99.asap.service.CryptoClient.seal(CryptoClient.java:34))- null
java.lang.NullPointerException
at java.net.InetAddress$Cache.put(InetAddress.java:779) ~[?:1.7.0_79]
at java.net.InetAddress.cacheAddresses(InetAddress.java:858) ~[?:1.7.0_79]
...
Posted on Wed, 13 May 2026 14:18:00 +0000 by why not