6. String constant pool 1. String pool The allocation of strings, like other object allocations, consumes high time and space costs. In order to improve performance and reduce memory overhead, the JVM has made some optimizations when instantiating string literals. In order to reduce the number of strings created in the JVM, the String class maintains a string constant pool. Whenever a string is created as a literal, the JVM will first check the string constant pool: if the string already exists in the pool , the instance reference in the pool is returned; if the string is not in the pool, a string is instantiated and placed in the pool. Java can perform such optimizations because strings are immutable and can be shared without worrying about data conflicts. For example: public class Program{ Public static void main(String[] args) { &nb
1. Java String Overview (Part 2)
##Introduction: The String class in Java is the most frequently used class in our daily development, but it is not easy to truly master this class. In order to restore the true and complete picture of the String class, the author first divides it into two blog posts to review the String class. The author starts from the Java memory model, combined with the source code of the String class in the JDK, especially the constant pool, immutability, object creation method of the String class, the relationship between the String class and flyweight mode, regular expressions, cloning and the three major strings. A comprehensive and accurate explanation of several aspects such as categories.
2. Java String Overview (Part 1)
##Introduction: The String class in Java is the most frequently used class in our daily development, but it is not easy to truly master this class. In order to restore the true and complete picture of the String class, the author first divides it into two blog posts to review the String class. The author starts from the Java memory model, combined with the source code of the String class in the JDK, especially the constant pool, immutability, object creation method of the String class, the relationship between the String class and flyweight mode, regular expressions, cloning and the three major strings. A comprehensive and accurate explanation of several aspects such as categories.
3.
java thread safety and immutability
##Introduction: A race condition occurs only if two threads access the same resource at the same time, and one or more threads write to this resource. If multiple threads read the same resource, a race condition will not occur. We can be sure that objects shared between threads are thread-safe by making the shared object immutable and not updated by any thread. Here is an example: public class ImmutableValue{ private int value = 0; public Immu
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