Isaura experiment

Some experiment with jdk 19

Build

An OpenJDK 19 or later build is required. At the time of this writing, virtual threads are a preview feature. That is why --enable-preview is provided below.

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Build with mvn:

mvn compile

JMH

Some experiments in [jmh] (https://github.com/openjdk/jmh). JMH is a library for benchmarks written in Java and other languages targeting the JVM.

The BenchReadingTextFile.java class test the number of operations for a simple task: generate tokens for a large sting, using two different methods:

• The method split of the String class
• The StringTokenizer class

In a system with

Available processors (cores): 12 Free memory (bytes): 849800928 Maximum memory (bytes): 4208984064 Total memory available to JVM (bytes): 975175680

the benchmarks between split and tokenizer are the following:

Benchmark	Mode	Cnt	Score	Units
BenchReadingTextFile.split	thrpt	5	≈ 10⁻³	ops/ns
BenchReadingTextFile.tokenizer	thrpt	5	2,990	ops/ns
BenchReadingTextFile.split	avgt	5	2291,476	ns/op
BenchReadingTextFile.tokenizer	avgt	5	0,320	ns/op

JOL

Some experiments in [jol] (https://github.com/openjdk/jol). JOL is a library that that helps you measure size of objects in java.

The TokenizerTest.java class tokenize and store in an HashMap a dataset of song lyrics.

The jol library output as follows:

Count	Avg	sum	Description
1	524304	524304	[Ljava.util.HashMap$Node;