Ankur
b7244ff9a2
Three verified programs (JDK 25, Spring Security 7.1.1, Spring Boot 4.1.1 dependency versions) backing the ankurm.com post: InheritableThreadLocal across thread models, @Async on a virtual-thread SimpleAsyncTaskExecutor (DelegatingSecurityContextExecutor vs ContextPropagatingTaskDecorator), and StructuredTaskScope.fork() propagation. Captured console output and docs chapters included.
45 lines
1.8 KiB
Java
45 lines
1.8 KiB
Java
package com.ankurm.vt;
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// Explained in docs/01-inheritable-threadlocal.md -- run via scripts/run-all.sh, output captured in docs/output/
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import java.util.concurrent.CountDownLatch;
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import java.util.concurrent.ExecutorService;
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import java.util.concurrent.Executors;
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import java.util.concurrent.TimeUnit;
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/** Confirms, with no Spring involved, how InheritableThreadLocal behaves for
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* (a) a fresh platform Thread, (b) a reused thread from a fixed pool, and
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* (c) a fresh virtual thread. */
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public class Demo1PlainThreadLocal {
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static final InheritableThreadLocal<String> CTX = new InheritableThreadLocal<>();
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public static void main(String[] args) throws Exception {
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System.out.println("=== Demo 1: InheritableThreadLocal across thread models ===");
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// (a) fresh platform Thread inherits at construction time
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CTX.set("request-A");
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Thread t = new Thread(() -> System.out.println("fresh platform thread sees: " + CTX.get()));
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t.start();
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t.join();
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// (b) reused thread from a fixed pool: the SECOND task on the same worker
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// still carries whatever was set when the pool thread was originally created
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ExecutorService pool = Executors.newFixedThreadPool(1);
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CTX.set("request-B");
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pool.submit(() -> System.out.println("pool thread, task 1, sees: " + CTX.get())).get();
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CTX.set("request-C"); // caller's context changed
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pool.submit(() -> System.out.println("pool thread, task 2 (reused), sees: " + CTX.get()
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+ " <-- stale, not request-C")).get();
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pool.shutdown();
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// (c) fresh virtual thread, never reused
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CTX.set("request-D");
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Thread vt = Thread.ofVirtual().start(() ->
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System.out.println("fresh virtual thread sees: " + CTX.get()));
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vt.join();
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CTX.remove();
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}
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}
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