ClassLoader close bug

Main.java

import java.io.BufferedReader;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.jar.JarOutputStream;
import java.util.zip.ZipEntry;
import static java.nio.charset.StandardCharsets.UTF_8;

public class Main {
  public static void main(String[] args) throws Exception {
    boolean skipClose = args.length > 0 && args[0].equals("skip");

    // Build resources.jar, whose file 'hello.txt' contains 'hello world'.
    File jarFile = new File("resources.jar");
    String resourceName = "hello.txt";
    String resourceContent = "hello world";
    try (JarOutputStream out = new JarOutputStream(new FileOutputStream(jarFile))) {
      out.putNextEntry(new ZipEntry(resourceName));
      out.write(resourceContent.getBytes(UTF_8));
    }
    URL[] jarFileUrls = {
      jarFile.toURI().toURL()
    };

    // Create a class loader B and start reading a resource with it.
    URLClassLoader loaderB = URLClassLoader.newInstance(jarFileUrls);
    InputStream inB = loaderB.getResourceAsStream(resourceName);

    // Create class loader A that reads the same jar file.
    URLClassLoader loaderA = URLClassLoader.newInstance(jarFileUrls);
    try (
      InputStream inA = loaderA.getResourceAsStream(resourceName);
      BufferedReader readerA = new BufferedReader(new InputStreamReader(inA))
    ) {
      if (readerA.readLine().equals(resourceContent)) {
        System.out.println("READ A SUCCESS");
      }
    }
    if (!skipClose) {
      loaderA.close();
    }

    // Finish reading the file with class loader B.
    try (BufferedReader readerB = new BufferedReader(new InputStreamReader(inB))) {
      if (readerB.readLine().equals(resourceContent)) {
        System.out.println("READ B SUCCESS");
      }
    }
  }
}

This crashes attempting to read from inB after loaderA.close().

$ javac Main.java  && java Main
READ A SUCCESS
Exception in thread "main" java.io.IOException: Stream closed
	at java.base/java.util.zip.InflaterInputStream.ensureOpen(InflaterInputStream.java:67)
	at java.base/java.util.zip.InflaterInputStream.read(InflaterInputStream.java:142)
	at java.base/java.io.FilterInputStream.read(FilterInputStream.java:132)
	at java.base/sun.nio.cs.StreamDecoder.readBytes(StreamDecoder.java:270)
	at java.base/sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:313)
	at java.base/sun.nio.cs.StreamDecoder.read(StreamDecoder.java:188)
	at java.base/java.io.InputStreamReader.read(InputStreamReader.java:177)
	at java.base/java.io.BufferedReader.fill(BufferedReader.java:162)
	at java.base/java.io.BufferedReader.readLine(BufferedReader.java:329)
	at java.base/java.io.BufferedReader.readLine(BufferedReader.java:396)
	at Main.main(Main.java:48)

If you pass the skip argument to the function to skip closing loaderA, it doesn’t crash:

$ javac Main.java  && java Main skip
READ A SUCCESS
READ B SUCCESS