A DESCRIPTION OF THE PROBLEM :
ResourceBundle.getBundle leaves the file open if the bundle is inside a jar file. This means the jar file cannot be deleted. I have a simple test program that demonstrates the problem -- it works fine with Java 8, but fails with Java 11 (and I tried early access 13). 

REGRESSION : Last worked in version 8u202

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Run the demo program with java 8 and with java 11, observe that the jar file is deleted ok when run with java 8, but cannot be deleted with java 11. 

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
I expect the jar file to be deleted. 
ACTUAL -
The jar file is not deleted (because it is left open). 

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Here's the source, but it requires (1) commons-io just for doing a simple file copy, (2) a mysql jdbc driver jar file. 
import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.Locale;
import java.util.ResourceBundle;

import org.apache.commons.io.FileUtils;

/**
 * This demonstrates a bug in Java 11 ResourceBundle. 
 * If you run this program with Java 8, the file is indeed deleted. 
 * If you run with Java 11, the file is not deleted. Ditto early release of Java 13.
 */
public class ResourceBundleBug {
    private static final String FILE = "mysql-connector-java-5.1.35-bin.jar";

    public static void main(String[] args) throws IOException {
        FileUtils.copyFileToDirectory(new File("res/" + FILE), FileUtils.getTempDirectory());
        URL url = new URL("file:" + FileUtils.getTempDirectoryPath() + "/" + FILE);
        URLClassLoader cl = new URLClassLoader(new URL[] {url}, null);
        ResourceBundle rb = ResourceBundle.getBundle("com.mysql.jdbc.LocalizedErrorMessages", Locale.US, cl);
        cl.close();
        File file = new File(FileUtils.getTempDirectoryPath() + "/" + FILE);
        System.out.println(file + " exists: " + file.exists());
        boolean deleted = file.delete();
        System.out.println("file was deleted: " + deleted);
    }
}

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CUSTOMER SUBMITTED WORKAROUND :
could not find one, would love to have one!

FREQUENCY : always